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docs/dcs/umn/ALL_META.TXT.json
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<a name="CacheCluster"></a><a name="CacheCluster"></a>
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<h1 class="topictitle1">Proxy Cluster Redis</h1>
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<div id="body1600250975360"><p id="CacheCluster__p16121033102019">DCS provides two types of cluster Redis instances: Proxy Cluster and Redis Cluster. Proxy Cluster uses Linux Virtual Server (LVS) and proxies. Redis Cluster is the native distributed implementation of Redis. Proxy Cluster instances are compatible with Redis 3.0, while Redis Cluster instances are compatible with Redis 4.0 and 5.0.</p>
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<p id="CacheCluster__p13103105219146">This section describes Proxy Cluster DCS Redis 3.0 instances.</p>
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<div class="note" id="CacheCluster__note134811721192210"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="CacheCluster__ul1758133822318"><li id="CacheCluster__li758133852319">A Proxy Cluster instance can be connected in the same way that a single-node or master/standby instance is connected, without any special settings on the client. You can use the IP address or domain name of the instance, and do not need to know or use the proxy or shard addresses.</li></ul>
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</div></div>
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<div class="section" id="CacheCluster__section861823615325"><h4 class="sectiontitle">Proxy Cluster DCS Redis 3.0 Instances</h4><p id="CacheCluster__p10878151913448">Proxy Cluster DCS Redis 3.0 instances are compatible with <a href="https://github.com/CodisLabs/codis" target="_blank" rel="noopener noreferrer">codis</a>. The specifications range from 64 GB to 1024 GB, meeting requirements for <strong id="CacheCluster__b13211893475612">millions of concurrent connections</strong> and <strong id="CacheCluster__b45541541375612">massive data cache</strong>. Distributed data storage and access is implemented by DCS, without requiring development or maintenance.</p>
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<p id="CacheCluster__p186619405101">Each Proxy Cluster instance consists of load balancers, proxies, cluster managers, and <a href="dcs-pd-200312004.html#dcs-pd-200312004__en-us_topic_0145956240_section20999323134412">shards</a>.</p>
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<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" id="CacheCluster__table13310319184" frame="border" border="1" rules="all"><caption><b>Table 1 </b>Specifications of Proxy Cluster DCS Redis 3.0 instances</caption><thead align="left"><tr id="CacheCluster__row9312131191817"><th align="left" class="cellrowborder" valign="top" width="28.52%" id="mcps1.3.4.4.2.4.1.1"><p id="CacheCluster__p13128115183">Total Memory</p>
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</th>
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<th align="left" class="cellrowborder" valign="top" width="36.13%" id="mcps1.3.4.4.2.4.1.2"><p id="CacheCluster__p231214131810">Proxies</p>
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</th>
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<th align="left" class="cellrowborder" valign="top" width="35.35%" id="mcps1.3.4.4.2.4.1.3"><p id="CacheCluster__p7312101121818">Shards</p>
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</th>
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</tr>
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</thead>
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<tbody><tr id="CacheCluster__row9312111101813"><td class="cellrowborder" valign="top" width="28.52%" headers="mcps1.3.4.4.2.4.1.1 "><p id="CacheCluster__p23121818185">64 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="36.13%" headers="mcps1.3.4.4.2.4.1.2 "><p id="CacheCluster__p13123116188">3</p>
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</td>
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<td class="cellrowborder" valign="top" width="35.35%" headers="mcps1.3.4.4.2.4.1.3 "><p id="CacheCluster__p1031211151819">8</p>
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</td>
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</tr>
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<tr id="CacheCluster__row15312516185"><td class="cellrowborder" valign="top" width="28.52%" headers="mcps1.3.4.4.2.4.1.1 "><p id="CacheCluster__p531216111189">128 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="36.13%" headers="mcps1.3.4.4.2.4.1.2 "><p id="CacheCluster__p143127110182">6</p>
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</td>
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<td class="cellrowborder" valign="top" width="35.35%" headers="mcps1.3.4.4.2.4.1.3 "><p id="CacheCluster__p33129111183">16</p>
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</td>
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</tr>
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<tr id="CacheCluster__row1131211118187"><td class="cellrowborder" valign="top" width="28.52%" headers="mcps1.3.4.4.2.4.1.1 "><p id="CacheCluster__p1731215112181">256 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="36.13%" headers="mcps1.3.4.4.2.4.1.2 "><p id="CacheCluster__p73123113185">8</p>
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</td>
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<td class="cellrowborder" valign="top" width="35.35%" headers="mcps1.3.4.4.2.4.1.3 "><p id="CacheCluster__p73121116182">32</p>
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</td>
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</tr>
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<tr id="CacheCluster__row5312131161819"><td class="cellrowborder" valign="top" width="28.52%" headers="mcps1.3.4.4.2.4.1.1 "><p id="CacheCluster__p531251181811">512 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="36.13%" headers="mcps1.3.4.4.2.4.1.2 "><p id="CacheCluster__p531214119184">16</p>
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</td>
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<td class="cellrowborder" valign="top" width="35.35%" headers="mcps1.3.4.4.2.4.1.3 "><p id="CacheCluster__p1831361191817">64</p>
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</td>
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</tr>
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</tbody>
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</table>
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</div>
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<div class="fignone" id="CacheCluster__fig10333132616620"><span class="figcap"><b>Figure 1 </b>Proxy Cluster DCS Redis instance architecture</span><br><span><img id="CacheCluster__image3165104135518" src="en-us_image_0296786822.png"></span></div>
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<p id="CacheCluster__p153106583326">Architecture description:</p>
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<ul id="CacheCluster__ul2171627184718"><li id="CacheCluster__li20179270479"><strong id="CacheCluster__b264814218559">VPC</strong><p id="CacheCluster__p89401530124718">All server nodes of the instance run in the same VPC.</p>
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<div class="note" id="CacheCluster__note04501339113"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="CacheCluster__p124516392019">For intra-VPC access, the client and the instance must be in the same VPC with specified security group rule configurations.</p>
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<p id="CacheCluster__p14803202620398">For details, see <a href="en-us_topic_0090662012.html">Security Group Configurations</a>.</p>
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</div></div>
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</li><li id="CacheCluster__li017927194718"><strong id="CacheCluster__b151362176475612">Application</strong><p id="CacheCluster__p36064574817">The client used to access the instance.</p>
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<p id="CacheCluster__p19314439510">DCS Redis instances can be accessed through open-source clients. For details about accessing DCS instances, see <a href="dcs-ug-0916002.html">Accessing an Instance</a>.</p>
|
||||
</li><li id="CacheCluster__li2171327154716"><strong id="CacheCluster__b1643674835519">LB-M/LB-S</strong><p id="CacheCluster__p170153810483">The load balancers, which are deployed in master/standby HA mode. The connection addresses (<strong id="CacheCluster__b28415079775612">IP address:Port</strong>) of the cluster DCS Redis instance are the addresses of the load balancers.</p>
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||||
</li><li id="CacheCluster__li81722784711"><strong id="CacheCluster__b7800450165513">Proxy</strong><p id="CacheCluster__p828195918488">The proxy server used to achieve high availability and process high-concurrency client requests.</p>
|
||||
<p id="CacheCluster__p168416553415">You can connect to a Proxy Cluster instance at the IP addresses of its proxies.</p>
|
||||
</li><li id="CacheCluster__li1517172714478"><strong id="CacheCluster__b135271352145516">Redis shard</strong><p id="CacheCluster__p1988663312352">A shard of the cluster.</p>
|
||||
<p id="CacheCluster__p44212486499">Each shard consists of a pair of master/standby nodes. If the master node becomes faulty, the standby node automatically takes over cluster services.</p>
|
||||
<p id="CacheCluster__p195614253518">If both the master and standby nodes of a shard are faulty, the cluster can still provide services but the data on the faulty shard is inaccessible.</p>
|
||||
</li><li id="CacheCluster__li1417327144713"><strong id="CacheCluster__b129817557557">Cluster manager</strong><p id="CacheCluster__p8379134205511">The cluster configuration managers, which store configurations and partitioning policies of the cluster. You cannot modify the information about the configuration managers.</p>
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</li></ul>
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</div>
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</div>
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<div>
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<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-pd-200312001.html">DCS Instance Types</a></div>
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</div>
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</div>
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docs/dcs/umn/CacheMasterSlave.html
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docs/dcs/umn/CacheMasterSlave.html
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<a name="CacheMasterSlave"></a><a name="CacheMasterSlave"></a>
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<h1 class="topictitle1">Master/Standby Redis</h1>
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<div id="body1600250974776"><p id="CacheMasterSlave__p11826145419223">This section describes master/standby DCS Redis instances. Three Redis versions are available for master/standby DCS Redis instances: Redis 3.0, Redis 4.0, and Redis 5.0.</p>
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||||
<div class="note" id="CacheMasterSlave__note67021744211"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="CacheMasterSlave__p157220441816">You cannot upgrade the Redis version for an instance. For example, a master/standby DCS Redis 3.0 instance cannot be upgraded to a master/standby DCS Redis 4.0 or 5.0 instance. If your service requires the features of higher Redis versions, create a DCS Redis instance of a higher version and then migrate data from the old instance to the new one.</p>
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</div></div>
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<div class="section" id="CacheMasterSlave__section2115135632817"><h4 class="sectiontitle">Features</h4><p id="CacheMasterSlave__p29361111432">Master/Standby DCS instances have higher availability and reliability than single-node DCS instances.</p>
|
||||
<p id="CacheMasterSlave__p152081045174518">Master/Standby DCS instances have the following features:</p>
|
||||
<ol id="CacheMasterSlave__ol12655131412"><li id="CacheMasterSlave__li191795312365"><strong id="CacheMasterSlave__b8393084757579">Data persistence and high reliability</strong><p id="CacheMasterSlave__p143153293617">By default, data persistence is enabled by both the master and the standby node of a master/standby instance.</p>
|
||||
<p id="CacheMasterSlave__p992216915351">The standby node of a DCS Redis instance is invisible to you. Only the master node provides data read/write operations.</p>
|
||||
</li><li id="CacheMasterSlave__li10688192120301"><strong id="CacheMasterSlave__b6852014317">Data synchronization</strong><p id="CacheMasterSlave__p2581425163010">Data in the master and standby nodes is kept consistent through incremental synchronization.</p>
|
||||
<div class="note" id="CacheMasterSlave__note1745795093018"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="CacheMasterSlave__p6458135018301">After recovering from a network exception or node fault, master/standby instances perform a full synchronization to ensure data consistency.</p>
|
||||
</div></div>
|
||||
</li><li id="CacheMasterSlave__li142654132115"><strong id="CacheMasterSlave__b117861923114313">Automatic master/standby switchover</strong><p id="CacheMasterSlave__p1922564615389">If the master node becomes faulty, the standby node takes over within 30 seconds, without requiring any service interruptions or manual operations.</p>
|
||||
</li><li id="CacheMasterSlave__li426374543318"><strong id="CacheMasterSlave__b415742710491">DR policies</strong><p id="CacheMasterSlave__p13889754193315">Each master/standby instance can be deployed across AZs with physically isolated power supplies and networks. Applications can also be deployed across AZs to achieve high availability for both data and applications.</p>
|
||||
</li></ol>
|
||||
</div>
|
||||
<div class="section" id="CacheMasterSlave__section1728321782810"><h4 class="sectiontitle">Architecture</h4><p id="CacheMasterSlave__p139021259112"><a href="#CacheMasterSlave__fig14477142816340">Figure 1</a> shows the architecture of master/standby DCS Redis instances.</p>
|
||||
<div class="note" id="CacheMasterSlave__note12240134982910"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="CacheMasterSlave__p11242249122915">To access a DCS Redis 3.0 instance, you must use port 6379. To access a DCS Redis 4.0 or 5.0 instance, you can customize the port. If no port is specified, the default port 6379 will be used. In the following architecture, port 6379 is used. If you have customized a port, replace <strong id="CacheMasterSlave__b185911833202410">6379</strong> with the actual port.</p>
|
||||
</div></div>
|
||||
<div class="fignone" id="CacheMasterSlave__fig14477142816340"><a name="CacheMasterSlave__fig14477142816340"></a><a name="fig14477142816340"></a><span class="figcap"><b>Figure 1 </b>Master/Standby DCS instance architecture</span><br><span><img id="CacheMasterSlave__image1555620406535" src="en-us_image_0296786164.png"></span></div>
|
||||
<p id="CacheMasterSlave__p153106583326">Architecture description:</p>
|
||||
<ul id="CacheMasterSlave__ul1631417191120"><li id="CacheMasterSlave__li20179270479"><strong id="CacheMasterSlave__b264814218559">VPC</strong><p id="CacheMasterSlave__p89401530124718">All server nodes of the instance run in the same VPC.</p>
|
||||
<div class="note" id="CacheMasterSlave__note04501339113"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="CacheMasterSlave__p124516392019">For intra-VPC access, the client and the instance must be in the same VPC with specified security group rule configurations.</p>
|
||||
<p id="CacheMasterSlave__p14803202620398">For details, see <a href="en-us_topic_0090662012.html">Security Group Configurations</a>.</p>
|
||||
</div></div>
|
||||
</li><li id="CacheMasterSlave__li017927194718"><strong id="CacheMasterSlave__b056638104917">Application</strong><p id="CacheMasterSlave__p36064574817">The Redis client of the instance, which is the application running on the ECS.</p>
|
||||
<p id="CacheMasterSlave__p20951317243">DCS Redis instances are compatible with the Redis protocol, and can be accessed through open-source clients. For details about accessing DCS instances, see <a href="dcs-ug-0916002.html">Accessing an Instance</a>.</p>
|
||||
</li><li id="CacheMasterSlave__li81722784711"><strong id="CacheMasterSlave__b18417232969">DCS instance</strong><p id="CacheMasterSlave__p141487982311">Indicates a master/standby DCS instance which has a master node and a standby node. By default, data persistence is enabled and data is synchronized between the two nodes.</p>
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||||
<p id="CacheMasterSlave__p1542317478287">DCS monitors the availability of the instance in real time. If the master node becomes faulty, the standby node becomes the master node and resumes service provisioning.</p>
|
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<p id="CacheMasterSlave__p828195918488">DCS Redis instances are accessed through port 6379 by default.</p>
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</li></ul>
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</div>
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</div>
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<div>
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<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-pd-200312001.html">DCS Instance Types</a></div>
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</div>
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</div>
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<a name="CacheProxy"></a><a name="CacheProxy"></a>
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<h1 class="topictitle1">Redis Cluster</h1>
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<div id="body1600250976541"><p id="CacheProxy__p7253192101916">This section describes Redis Cluster DCS Redis 4.0 and 5.0 instances.</p>
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<div class="section" id="CacheProxy__section880163191618"><h4 class="sectiontitle">Redis Cluster DCS Redis 4.0 and 5.0 Instances</h4><p id="CacheProxy__p1977021012338">The Redis Cluster instance type provided by DCS is compatible with the <a href="https://redis.io/topics/cluster-spec" target="_blank" rel="noopener noreferrer">native Redis Cluster</a>, which uses smart clients and a distributed architecture to perform sharding.</p>
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<p id="CacheProxy__p164954315218"><a href="#CacheProxy__table3552324111">Table 1</a> lists the shard specification for different instance specifications.</p>
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<p id="CacheProxy__p17223016111"><strong id="CacheProxy__b94915132075659">Specification per shard=Instance specification/Number of shards</strong>. For example, if a 48 GB instance has 6 shards, the specification of each shard is 48 GB/6 = 8 GB.</p>
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<div class="tablenoborder"><a name="CacheProxy__table3552324111"></a><a name="table3552324111"></a><table cellpadding="4" cellspacing="0" summary="" id="CacheProxy__table3552324111" frame="border" border="1" rules="all"><caption><b>Table 1 </b>Specifications of Redis Cluster DCS instances</caption><thead align="left"><tr id="CacheProxy__row65521623113"><th align="left" class="cellrowborder" valign="top" width="44.12%" id="mcps1.3.2.5.2.3.1.1"><p id="CacheProxy__p1955210211118">Total Memory</p>
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</th>
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<th align="left" class="cellrowborder" valign="top" width="55.879999999999995%" id="mcps1.3.2.5.2.3.1.2"><p id="CacheProxy__p04843421456">Shards</p>
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</th>
|
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</tr>
|
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</thead>
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<tbody><tr id="CacheProxy__row155314218115"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p491514405611">4 GB/8 GB/16 GB/24 GB/32 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p207903579620">3</p>
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</td>
|
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</tr>
|
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<tr id="CacheProxy__row1731117227614"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p99166401567">48 GB</p>
|
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</td>
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<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p1779095710616">6</p>
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</td>
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</tr>
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<tr id="CacheProxy__row113126221669"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p891617401862">64 GB</p>
|
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</td>
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<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p97906571561">8</p>
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</td>
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</tr>
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<tr id="CacheProxy__row10313162217619"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p19161140362">96 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p879011574611">12</p>
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</td>
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</tr>
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<tr id="CacheProxy__row93136221568"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p15916164015619">128 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p1679065712610">16</p>
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</td>
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</tr>
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<tr id="CacheProxy__row123147221965"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p1591613409619">192 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p137910577616">24</p>
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</td>
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</tr>
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<tr id="CacheProxy__row1297218281269"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p4916140966">256 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p87911957860">32</p>
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</td>
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</tr>
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<tr id="CacheProxy__row14566154853519"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p356774883515">384 GB</p>
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</td>
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<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p10567548133513">48</p>
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</td>
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</tr>
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<tr id="CacheProxy__row8567124814359"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p14311185913513">512 GB</p>
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</td>
|
||||
<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p20567184883518">64</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr id="CacheProxy__row7567114814356"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p967654163618">768 GB</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p13568194813354">96</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr id="CacheProxy__row1656844810350"><td class="cellrowborder" valign="top" width="44.12%" headers="mcps1.3.2.5.2.3.1.1 "><p id="CacheProxy__p209424813617">1024 GB</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="55.879999999999995%" headers="mcps1.3.2.5.2.3.1.2 "><p id="CacheProxy__p155682483350">128</p>
|
||||
</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
</div>
|
||||
<ul id="CacheProxy__ul123731121185515"><li id="CacheProxy__li3970143612556">Distributed architecture<p id="CacheProxy__p6111153985512"><a name="CacheProxy__li3970143612556"></a><a name="li3970143612556"></a>Any node in a Redis Cluster can receive requests. Received requests are then redirected to the right node for processing. Each node consists of a subset of one master and one (by default) or multiple replicas. The master or replica roles are determined through an election algorithm.</p>
|
||||
<div class="fignone" id="CacheProxy__fig736144082814"><span class="figcap"><b>Figure 1 </b>Distributed architecture of Redis Cluster</span><br><span><img id="CacheProxy__image0855192718314" src="en-us_image_0277578727.png"></span></div>
|
||||
</li><li id="CacheProxy__li1693714855516">Presharding<p id="CacheProxy__p2019185113552"><a name="CacheProxy__li1693714855516"></a><a name="li1693714855516"></a>There are 16,384 hash slots in each Redis Cluster. The mapping between hash slots and Redis nodes is stored in Redis Servers. To compute what is the hash slot of a given key, simply take the CRC16 of the key modulo 16384. Example command output</p>
|
||||
<div class="fignone" id="CacheProxy__fig114922024115011"><span class="figcap"><b>Figure 2 </b>Redis Cluster presharding</span><br><span><img id="CacheProxy__image1087382672319" src="en-us_image_0000001280621500.png"></span></div>
|
||||
</li></ul>
|
||||
</div>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-pd-200312001.html">DCS Instance Types</a></div>
|
||||
</div>
|
||||
</div>
|
||||
32
docs/dcs/umn/CacheSingleNode.html
Normal file
32
docs/dcs/umn/CacheSingleNode.html
Normal file
@ -0,0 +1,32 @@
|
||||
<a name="CacheSingleNode"></a><a name="CacheSingleNode"></a>
|
||||
|
||||
<h1 class="topictitle1">Single-Node Redis</h1>
|
||||
<div id="body1600250973735"><p id="CacheSingleNode__p138101212403">Three Redis versions are available for single-node DCS Redis instances: Redis 3.0, Redis 4.0, and Redis 5.0.</p>
|
||||
<div class="section" id="CacheSingleNode__section19260552619"><h4 class="sectiontitle">Features</h4><ol id="CacheSingleNode__ol67507623011"><li id="CacheSingleNode__li107501061301">Low system overhead and high QPS<p id="CacheSingleNode__p22461983014"><a name="CacheSingleNode__li107501061301"></a><a name="li107501061301"></a>Single-node instances do not support data synchronization or data persistence, reducing system overhead and supporting higher concurrency. QPS of single-node DCS Redis instances reaches up to 100,000.</p>
|
||||
</li><li id="CacheSingleNode__li77501762306">Process monitoring and automatic fault recovery<p id="CacheSingleNode__p1917103533114"><a name="CacheSingleNode__li77501762306"></a><a name="li77501762306"></a>With an HA monitoring mechanism, if a single-node DCS instance becomes faulty, a new process is started within 30 seconds to resume service provisioning.</p>
|
||||
</li><li id="CacheSingleNode__li975015614309">Out-of-the-box usability and no data persistence<p id="CacheSingleNode__p667242253214"><a name="CacheSingleNode__li975015614309"></a><a name="li975015614309"></a>Single-node DCS instances can be used out of the box because they do not involve data loading. If your service requires high QPS, you can warm up the data beforehand to avoid strong concurrency impact on the backend database.</p>
|
||||
</li><li id="CacheSingleNode__li11291719163215">Low-cost and suitable for development and testing<p id="CacheSingleNode__p763085119554"><a name="CacheSingleNode__li11291719163215"></a><a name="li11291719163215"></a>Single-node instances are 40% cheaper than master/standby DCS instances, suitable for setting up development or testing environments.</p>
|
||||
</li></ol>
|
||||
<p id="CacheSingleNode__p188211915114319">In summary, single-node DCS instances support highly concurrent read/write operations, but do not support data persistence. Data will be deleted after instances are restarted. They are suitable for scenarios which do not require data persistence, such as database front-end caching, to accelerate access and ease the concurrency load off the backend. If the desired data does not exist in the cache, requests will go to the database. When restarting the service or the DCS instance, you can pre-generate cache data from the disk database to relieve pressure on the backend during startup.</p>
|
||||
</div>
|
||||
<div class="section" id="CacheSingleNode__section350919180019"><h4 class="sectiontitle">Architecture</h4><p id="CacheSingleNode__p169821159154813"><a href="#CacheSingleNode__fig15457185394718">Figure 1</a> shows the architecture of single-node DCS Redis instances.</p>
|
||||
<div class="note" id="CacheSingleNode__note12240134982910"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="CacheSingleNode__p11242249122915">To access a DCS Redis 3.0 instance, you must use port 6379. To access a DCS Redis 4.0 or 5.0 instance, you can customize the port. If no port is specified, the default port 6379 will be used. In the following architecture, port 6379 is used. If you have customized a port, replace <strong id="CacheSingleNode__b1442135013241">6379</strong> with the actual port.</p>
|
||||
</div></div>
|
||||
<div class="fignone" id="CacheSingleNode__fig15457185394718"><a name="CacheSingleNode__fig15457185394718"></a><a name="fig15457185394718"></a><span class="figcap"><b>Figure 1 </b>Single-node DCS Redis instance architecture</span><br><span><img id="CacheSingleNode__image9134201365216" src="en-us_image_0296784660.png"></span></div>
|
||||
<p id="CacheSingleNode__p153106583326">Architecture description:</p>
|
||||
<ul id="CacheSingleNode__ul1631417191120"><li id="CacheSingleNode__li20179270479"><strong id="CacheSingleNode__b264814218559">VPC</strong><p id="CacheSingleNode__p89401530124718">All server nodes of the instance run in the same VPC.</p>
|
||||
<div class="note" id="CacheSingleNode__note04501339113"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="CacheSingleNode__p124516392019">For intra-VPC access, the client and the instance must be in the same VPC with specified security group rule configurations.</p>
|
||||
<p id="CacheSingleNode__p14803202620398">For details, see <a href="en-us_topic_0090662012.html">Security Group Configurations</a>.</p>
|
||||
</div></div>
|
||||
</li><li id="CacheSingleNode__li017927194718"><strong id="CacheSingleNode__b386793812488">Application</strong><p id="CacheSingleNode__p36064574817">The client of the instance, which is the application running on an Elastic Cloud Server (ECS).</p>
|
||||
<p id="CacheSingleNode__p19314439510">DCS Redis instances are compatible with the Redis protocol, and can be accessed through open-source clients. For details about accessing DCS instances, see <a href="dcs-ug-0916002.html">Accessing an Instance</a>.</p>
|
||||
</li><li id="CacheSingleNode__li81722784711"><strong id="CacheSingleNode__b18417232969">DCS instance</strong><p id="CacheSingleNode__p18848151812814">A single-node DCS instance, which has only one node and one Redis process.</p>
|
||||
<p id="CacheSingleNode__p74831359122616">DCS monitors the availability of the instance in real time. If the Redis process becomes faulty, DCS starts a new process to resume service provisioning.</p>
|
||||
</li></ul>
|
||||
</div>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-pd-200312001.html">DCS Instance Types</a></div>
|
||||
</div>
|
||||
</div>
|
||||
27
docs/dcs/umn/GlobalDRPolicy.html
Normal file
27
docs/dcs/umn/GlobalDRPolicy.html
Normal file
@ -0,0 +1,27 @@
|
||||
<a name="GlobalDRPolicy"></a><a name="GlobalDRPolicy"></a>
|
||||
|
||||
<h1 class="topictitle1">HA and DR Policies</h1>
|
||||
<div id="body8662426"><p id="GlobalDRPolicy__en-us_topic_0161126124_p8060118">Whether you use DCS as the frontend cache or backend data store, DCS is always ready to ensure data reliability and service availability. The following figure shows the evolution of DCS DR architectures.</p>
|
||||
<div class="fignone" id="GlobalDRPolicy__en-us_topic_0161126124_fig16302053154911"><span class="figcap"><b>Figure 1 </b>DCS DR architecture evolution</span><br><span><img id="GlobalDRPolicy__en-us_topic_0161126124_image153322437119" src="en-us_image_0266235346.png"></span></div>
|
||||
<p id="GlobalDRPolicy__en-us_topic_0161126124_p196901189533">To meet the reliability requirements of your data and services, you can choose to deploy your DCS instance within a single AZ or across AZs.</p>
|
||||
<div class="section" id="GlobalDRPolicy__en-us_topic_0161126124_section9873193151517"><h4 class="sectiontitle">Single-AZ HA</h4><p id="GlobalDRPolicy__en-us_topic_0161126124_p11449191363119">Single-AZ deployment means deploying an instance within a physical equipment room. DCS provides process/service HA, data persistence, and hot standby DR policies for different types of DCS instances.</p>
|
||||
<p id="GlobalDRPolicy__en-us_topic_0161126124_p1795194162611"><strong id="GlobalDRPolicy__en-us_topic_0161126124_b67201447135919">Single-node DCS instance</strong>: When DCS detects a process fault, a new process is started to ensure service HA.</p>
|
||||
<div class="fignone" id="GlobalDRPolicy__en-us_topic_0161126124_fig175040231000"><span class="figcap"><b>Figure 2 </b>HA for a single-node DCS instance deployed within an AZ</span><br><span><img class="vsd" id="GlobalDRPolicy__en-us_topic_0161126124_image164201427202219" src="en-us_image_0266235448.png"></span></div>
|
||||
<p id="GlobalDRPolicy__en-us_topic_0161126124_p398014445284"><strong id="GlobalDRPolicy__en-us_topic_0161126124_b166451111105">Master/Standby DCS instance</strong>: Data is persisted to disk in the master node and incrementally synchronized and persisted to the standby node, achieving hot standby and data persistence.</p>
|
||||
<div class="fignone" id="GlobalDRPolicy__en-us_topic_0161126124_fig9238184592511"><span class="figcap"><b>Figure 3 </b>HA for a master/standby DCS instance deployed within an AZ</span><br><span><img class="vsd" id="GlobalDRPolicy__en-us_topic_0161126124_image169901810234" src="en-us_image_0266235321.png"></span></div>
|
||||
<p id="GlobalDRPolicy__en-us_topic_0161126124_p81313812814"><strong id="GlobalDRPolicy__en-us_topic_0161126124_b568512479108">Cluster DCS instance</strong>: Similar to a master/standby instance, data in each shard (instance process) of a cluster instance is synchronized between master and standby nodes and persisted on both nodes.</p>
|
||||
<div class="fignone" id="GlobalDRPolicy__en-us_topic_0161126124_fig18044436405"><span class="figcap"><b>Figure 4 </b>HA for a cluster DCS instance deployed within an AZ</span><br><span><img class="vsd" id="GlobalDRPolicy__en-us_topic_0161126124_image03261413152416" src="en-us_image_0266235394.png"></span></div>
|
||||
</div>
|
||||
<div class="section" id="GlobalDRPolicy__en-us_topic_0161126124_section724471151511"><h4 class="sectiontitle">Cross-AZ DR</h4><p id="GlobalDRPolicy__en-us_topic_0161126124_p73698714013">The master and standby nodes of a master/standby or cluster DCS instance can be deployed across AZs (in different equipment rooms). Power supplies and networks of different AZs are physically isolated. When a fault occurs in the AZ where the master node is deployed, the standby node connects to the client and takes over data read and write operations.</p>
|
||||
<div class="fignone" id="GlobalDRPolicy__en-us_topic_0161126124_fig2046754742112"><span class="figcap"><b>Figure 5 </b>Cross-AZ deployment of a master/standby DCS instance</span><br><span><img class="vsd" id="GlobalDRPolicy__en-us_topic_0161126124_image1079294613241" src="en-us_image_0266235441.png"></span></div>
|
||||
<div class="note" id="GlobalDRPolicy__en-us_topic_0161126124_note41824212218"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="GlobalDRPolicy__en-us_topic_0161126124_p17181423225">This mechanism applies in a similar way to a cluster DCS instance. Each shard (process) is deployed across AZs.</p>
|
||||
</div></div>
|
||||
<p id="GlobalDRPolicy__en-us_topic_0161126124_p1333015655118">When creating a master/standby or cluster DCS instance, select a standby AZ that is different from the primary AZ.</p>
|
||||
<p id="GlobalDRPolicy__p1110819147496">Backup, configuration modification, and password change functions cannot be used during the fault.</p>
|
||||
</div>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-pd-0326001.html">Service Overview</a></div>
|
||||
</div>
|
||||
</div>
|
||||
3
docs/dcs/umn/PARAMETERS.txt
Normal file
3
docs/dcs/umn/PARAMETERS.txt
Normal file
@ -0,0 +1,3 @@
|
||||
version=""
|
||||
language="en-us"
|
||||
type=""
|
||||
19
docs/dcs/umn/PurchasePreparation.html
Normal file
19
docs/dcs/umn/PurchasePreparation.html
Normal file
@ -0,0 +1,19 @@
|
||||
<a name="PurchasePreparation"></a><a name="PurchasePreparation"></a>
|
||||
|
||||
<h1 class="topictitle1">Identifying Requirements</h1>
|
||||
<div id="body8662426"><p id="PurchasePreparation__en-us_topic_0168497785_p35841666509">Before creating a DCS instance, identify your requirements and complete the following preparations:</p>
|
||||
<ol id="PurchasePreparation__en-us_topic_0168497785_ol8797163185312"><li id="PurchasePreparation__en-us_topic_0168497785_li479893115317">Decide on the required cache engine version.<p id="PurchasePreparation__en-us_topic_0168497785_p1570920515610"><a name="PurchasePreparation__en-us_topic_0168497785_li479893115317"></a><a name="en-us_topic_0168497785_li479893115317"></a>Different Redis versions have different features. For details, see <a href="RedisDifference.html">Comparing Redis Versions</a>.</p>
|
||||
</li><li id="PurchasePreparation__en-us_topic_0168497785_li479873115320">Decide on the required instance type.<p id="PurchasePreparation__en-us_topic_0168497785_p7482257123713"><a name="PurchasePreparation__en-us_topic_0168497785_li479873115320"></a><a name="en-us_topic_0168497785_li479873115320"></a>DCS provides single-node, master/standby, Proxy Cluster, and Redis Cluster types of instances. Each type has its own architecture. For details about the instance architectures, see <a href="dcs-pd-200312001.html">DCS Instance Types</a>.</p>
|
||||
</li><li id="PurchasePreparation__en-us_topic_0168497785_li17984375315">Decide on the required instance specification.<p id="PurchasePreparation__p186331251181116"><a name="PurchasePreparation__en-us_topic_0168497785_li17984375315"></a><a name="en-us_topic_0168497785_li17984375315"></a>Each specification specifies the maximum available memory, number of connections, and bandwidth. For details, see <a href="en-us_topic_0054235835.html">DCS Instance Specifications</a>.</p>
|
||||
</li><li id="PurchasePreparation__en-us_topic_0168497785_li187982355319">Decide on the region and whether cross-AZ deployment is required.<p id="PurchasePreparation__en-us_topic_0168497785_p92195185414"><a name="PurchasePreparation__en-us_topic_0168497785_li187982355319"></a><a name="en-us_topic_0168497785_li187982355319"></a>Choose a region closest to your application to reduce latency.</p>
|
||||
<p id="PurchasePreparation__en-us_topic_0168497785_p15928161731110">A region consists of multiple availability zones (AZs) with physically isolated power supplies and networks. Master/standby and cluster DCS instances can be deployed across AZs.</p>
|
||||
<div class="note" id="PurchasePreparation__en-us_topic_0168497785_note6826904912"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="PurchasePreparation__en-us_topic_0168497785_ul3826100994"><li id="PurchasePreparation__en-us_topic_0168497785_li0826200195">If a master/standby or cluster DCS instance is deployed across AZs, faults in an AZ do not affect cache nodes in other AZs. This is because when the master node is faulty, the standby cache node will automatically become the master node to provide services. Such deployment achieves better disaster recovery.</li><li id="PurchasePreparation__en-us_topic_0168497785_li182617019920">Deploying a DCS instance across AZs slightly reduces network efficiency compared with deploying an instance within an AZ. Therefore, if a DCS instance is deployed across AZs, synchronization between master and standby cache nodes is slightly less efficient.</li></ul>
|
||||
</div></div>
|
||||
</li><li id="PurchasePreparation__en-us_topic_0168497785_li279803125315">Decide whether backup policies are required.<p id="PurchasePreparation__p15224832164414"><a name="PurchasePreparation__en-us_topic_0168497785_li279803125315"></a><a name="en-us_topic_0168497785_li279803125315"></a>Currently, backup policies can be configured only for master/standby and cluster DCS instances. For details about backup and restoration, see <a href="en-us_topic_0079835992.html">Overview</a>.</p>
|
||||
</li></ol>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-ug-0312003.html">Creating an Instance</a></div>
|
||||
</div>
|
||||
</div>
|
||||
76
docs/dcs/umn/RedisDifference.html
Normal file
76
docs/dcs/umn/RedisDifference.html
Normal file
@ -0,0 +1,76 @@
|
||||
<a name="RedisDifference"></a><a name="RedisDifference"></a>
|
||||
|
||||
<h1 class="topictitle1">Comparing Redis Versions</h1>
|
||||
<div id="body8662426"><p id="RedisDifference__en-us_topic_0147231413_p17821915171115">When creating a DCS Redis instance, you can select the cache engine version and the instance type.</p>
|
||||
<ul id="RedisDifference__en-us_topic_0147231413_ul0128672131"><li id="RedisDifference__en-us_topic_0147231413_li17128775131"><strong id="RedisDifference__en-us_topic_0147231413_b10691123654311">Version</strong><p id="RedisDifference__en-us_topic_0147231413_p48271921131515">DCS supports Redis 3.0, 4.0, and 5.0. The following table describes the differences between these versions.</p>
|
||||
|
||||
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" id="RedisDifference__en-us_topic_0147231413_table3788103816552" frame="border" border="1" rules="all"><caption><b>Table 1 </b>Differences between Redis versions</caption><thead align="left"><tr id="RedisDifference__en-us_topic_0147231413_row478910381556"><th align="left" class="cellrowborder" valign="top" width="16.041604160416043%" id="mcps1.3.2.1.3.2.4.1.1"><p id="RedisDifference__en-us_topic_0147231413_p3789193875510">Feature</p>
|
||||
</th>
|
||||
<th align="left" class="cellrowborder" valign="top" width="42.114211421142116%" id="mcps1.3.2.1.3.2.4.1.2"><p id="RedisDifference__en-us_topic_0147231413_p5789183810553">Redis 3.0</p>
|
||||
</th>
|
||||
<th align="left" class="cellrowborder" valign="top" width="41.84418441844185%" id="mcps1.3.2.1.3.2.4.1.3"><p id="RedisDifference__en-us_topic_0147231413_p10790938135520">Redis 4.0 and Redis 5.0</p>
|
||||
</th>
|
||||
</tr>
|
||||
</thead>
|
||||
<tbody><tr id="RedisDifference__en-us_topic_0147231413_row779019388558"><td class="cellrowborder" valign="top" width="16.041604160416043%" headers="mcps1.3.2.1.3.2.4.1.1 "><p id="RedisDifference__en-us_topic_0147231413_p10790163875516">Instance deployment mode</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="42.114211421142116%" headers="mcps1.3.2.1.3.2.4.1.2 "><p id="RedisDifference__en-us_topic_0147231413_p16790133818559">Based on VMs</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="41.84418441844185%" headers="mcps1.3.2.1.3.2.4.1.3 "><p id="RedisDifference__en-us_topic_0147231413_p879013811559">Containerized based on physical servers</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr id="RedisDifference__en-us_topic_0147231413_row1379017382554"><td class="cellrowborder" valign="top" width="16.041604160416043%" headers="mcps1.3.2.1.3.2.4.1.1 "><p id="RedisDifference__en-us_topic_0147231413_p679020384551">Time required for creating an instance</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="42.114211421142116%" headers="mcps1.3.2.1.3.2.4.1.2 "><p id="RedisDifference__en-us_topic_0147231413_p197904387556">3–15 minutes, or 10–30 minutes for cluster instances.</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="41.84418441844185%" headers="mcps1.3.2.1.3.2.4.1.3 "><p id="RedisDifference__en-us_topic_0147231413_p1679063811551">8 seconds</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr id="RedisDifference__en-us_topic_0147231413_row4790173817555"><td class="cellrowborder" valign="top" width="16.041604160416043%" headers="mcps1.3.2.1.3.2.4.1.1 "><p id="RedisDifference__en-us_topic_0147231413_p679093885516">QPS</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="42.114211421142116%" headers="mcps1.3.2.1.3.2.4.1.2 "><p id="RedisDifference__en-us_topic_0147231413_p2790938135512">100,000 QPS per node</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="41.84418441844185%" headers="mcps1.3.2.1.3.2.4.1.3 "><p id="RedisDifference__en-us_topic_0147231413_p16165906166">100,000 QPS per node</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr id="RedisDifference__en-us_topic_0147231413_row1179083875511"><td class="cellrowborder" valign="top" width="16.041604160416043%" headers="mcps1.3.2.1.3.2.4.1.1 "><p id="RedisDifference__en-us_topic_0147231413_p1790838175515">Instance type</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="42.114211421142116%" headers="mcps1.3.2.1.3.2.4.1.2 "><p id="RedisDifference__en-us_topic_0147231413_p1279023812559">Single-node, master/standby, and Proxy Cluster</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="41.84418441844185%" headers="mcps1.3.2.1.3.2.4.1.3 "><p id="RedisDifference__en-us_topic_0147231413_p4790438135511">Single-node, master/standby and Redis Cluster</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr id="RedisDifference__en-us_topic_0147231413_row14584340310"><td class="cellrowborder" valign="top" width="16.041604160416043%" headers="mcps1.3.2.1.3.2.4.1.1 "><p id="RedisDifference__en-us_topic_0147231413_p258511410316">Instance total memory</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="42.114211421142116%" headers="mcps1.3.2.1.3.2.4.1.2 "><p id="RedisDifference__en-us_topic_0147231413_p1058513418319">Ranges from 2 GB, 4 GB, 8 GB, to 1024 GB.</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="41.84418441844185%" headers="mcps1.3.2.1.3.2.4.1.3 "><p id="RedisDifference__en-us_topic_0147231413_p1859119191714">Regular specifications range from 2 GB, 4 GB, 8 GB, to 1024 GB. Small specifications, such as 128 MB, 256 MB, 512 MB, and 1 GB, are also available for single-node and master/standby instances. </p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr id="RedisDifference__en-us_topic_0147231413_row10764145318"><td class="cellrowborder" valign="top" width="16.041604160416043%" headers="mcps1.3.2.1.3.2.4.1.1 "><p id="RedisDifference__en-us_topic_0147231413_p1764134139">Scale-up or scale-down</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="42.114211421142116%" headers="mcps1.3.2.1.3.2.4.1.2 "><p id="RedisDifference__en-us_topic_0147231413_p1376414416313">Online scale-up and scale-down</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="41.84418441844185%" headers="mcps1.3.2.1.3.2.4.1.3 "><p id="RedisDifference__en-us_topic_0147231413_p1176444633">Online scale-up and scale-down</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr id="RedisDifference__en-us_topic_0147231413_row0956741836"><td class="cellrowborder" valign="top" width="16.041604160416043%" headers="mcps1.3.2.1.3.2.4.1.1 "><p id="RedisDifference__en-us_topic_0147231413_p5956941431">Backup and restoration</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="42.114211421142116%" headers="mcps1.3.2.1.3.2.4.1.2 "><p id="RedisDifference__en-us_topic_0147231413_p495617416314">Supported for master/standby and cluster instances</p>
|
||||
</td>
|
||||
<td class="cellrowborder" valign="top" width="41.84418441844185%" headers="mcps1.3.2.1.3.2.4.1.3 "><p id="RedisDifference__en-us_topic_0147231413_p99561648316">Supported for master/standby and cluster instances</p>
|
||||
</td>
|
||||
</tr>
|
||||
</tbody>
|
||||
</table>
|
||||
</div>
|
||||
<div class="note" id="RedisDifference__en-us_topic_0147231413_note1177317222288"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="RedisDifference__en-us_topic_0147231413_p677412212815">The underlying architectures vary by Redis version. Once a Redis version is chosen, it cannot be changed. For example, you cannot upgrade a DCS Redis 3.0 instance to Redis 4.0 or 5.0. If you require a higher Redis version, create a new instance that meets your requirements and then migrate data from the old instance to the new one.</p>
|
||||
</div></div>
|
||||
</li><li id="RedisDifference__en-us_topic_0147231413_li1612811716135"><strong id="RedisDifference__en-us_topic_0147231413_b1293715259192">Instance type</strong><p id="RedisDifference__en-us_topic_0147231413_p1982518509152">Select from single-node, master/standby, and cluster types. For details about their architectures and application scenarios, see <a href="dcs-pd-200312001.html">DCS Instance Types</a>.</p>
|
||||
</li></ul>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-pd-0326001.html">Service Overview</a></div>
|
||||
</div>
|
||||
</div>
|
||||
23
docs/dcs/umn/cache-instance-password.html
Normal file
23
docs/dcs/umn/cache-instance-password.html
Normal file
@ -0,0 +1,23 @@
|
||||
<a name="cache-instance-password"></a><a name="cache-instance-password"></a>
|
||||
|
||||
<h1 class="topictitle1">DCS Instance Passwords</h1>
|
||||
<div id="body8662426"><p id="cache-instance-password__en-us_topic_0157078204_p985222322411">Passwords can be configured to control access to your DCS instances, ensuring the security of your data.</p>
|
||||
<div class="note" id="cache-instance-password__note5179111618488"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="cache-instance-password__p5419067515298">After 5 consecutive incorrect password attempts, the account for accessing the chosen DCS instance will be locked for 5 minutes. Passwords cannot be changed during the lockout period.</p>
|
||||
<p id="cache-instance-password__p1537135716305">The password must meet the following requirements:</p>
|
||||
<ul id="cache-instance-password__ul1537117578305"><li id="cache-instance-password__li8371195793011">Cannot be left blank.</li><li id="cache-instance-password__li57052386429">Cannot be the same as the old password.</li><li id="cache-instance-password__li18371185712308">Can contain 8 to 32 characters.</li><li id="cache-instance-password__li13371115743020">Must contain at least three of the following character types:<ul id="cache-instance-password__ul10371357103018"><li id="cache-instance-password__li437195713308">Lowercase letters</li><li id="cache-instance-password__li16371125703015">Uppercase letters</li><li id="cache-instance-password__li1737111574305">Digits</li><li id="cache-instance-password__li113711573309">special characters (`~!@#$^&*()-_=+\|{}:,<.>/?)</li></ul>
|
||||
</li></ul>
|
||||
</div></div>
|
||||
<div class="section" id="cache-instance-password__en-us_topic_0157078204_section4863101016391"><h4 class="sectiontitle">Using Passwords Securely</h4><ol id="cache-instance-password__en-us_topic_0157078204_ol2887434144012"><li id="cache-instance-password__en-us_topic_0157078204_li38871534174016">Hide the password when using redis-cli.<p id="cache-instance-password__en-us_topic_0157078204_p188144904012"><a name="cache-instance-password__en-us_topic_0157078204_li38871534174016"></a><a name="en-us_topic_0157078204_li38871534174016"></a>If the <strong id="cache-instance-password__en-us_topic_0157078204_b188123233553">-a <password></strong> option is used in redis-cli in Linux, the password is prone to leakage because it is logged and kept in the history. You are advised not to use <strong id="cache-instance-password__b266115341594">-a <password></strong> when running commands in redis-cli. After connecting to Redis, run the <strong id="cache-instance-password__b136618340913">auth</strong> command to complete authentication as shown in the following example:</p>
|
||||
<pre class="screen" id="cache-instance-password__en-us_topic_0157078204_screen0635125654716">$ redis-cli -h 192.168.0.148 -p 6379
|
||||
redis 192.168.0.148:6379><strong id="cache-instance-password__en-us_topic_0157078204_b535814614336">auth</strong> <em id="cache-instance-password__en-us_topic_0157078204_i4796183254916">yourPassword</em>
|
||||
OK
|
||||
redis 192.168.0.148:6379></pre>
|
||||
</li><li id="cache-instance-password__en-us_topic_0157078204_li1188711348407">Use interactive password authentication or switch between users with different permissions.<p id="cache-instance-password__en-us_topic_0157078204_p3411122543917"><a name="cache-instance-password__en-us_topic_0157078204_li1188711348407"></a><a name="en-us_topic_0157078204_li1188711348407"></a>If the script involves DCS instance access, use interactive password authentication. To enable automatic script execution, manage the script as another user and authorize execution using sudo.</p>
|
||||
</li><li id="cache-instance-password__en-us_topic_0157078204_li1886081173813">Use an encryption module in your application to encrypt the password.</li></ol>
|
||||
</div>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-ug-0312039.html">Managing Passwords</a></div>
|
||||
</div>
|
||||
</div>
|
||||
26
docs/dcs/umn/dcs-faq-0326019.html
Normal file
26
docs/dcs/umn/dcs-faq-0326019.html
Normal file
@ -0,0 +1,26 @@
|
||||
<a name="dcs-faq-0326019"></a><a name="dcs-faq-0326019"></a>
|
||||
|
||||
|
||||
<h1 class="topictitle1">FAQs</h1>
|
||||
|
||||
<div id="body1585185912660"><p id="dcs-faq-0326019__p8060118"></p>
|
||||
</div>
|
||||
|
||||
<div>
|
||||
<ul class="ullinks">
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0326020.html">Client and Network Connection</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0326021.html">Redis Usage</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-190921003.html">Redis Commands</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0326022.html">Instance Scaling and Upgrade</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0326023.html">Monitoring and Alarm</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0326024.html">Data Backup, Export, and Migration</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-191204001.html">Master/Standby Switchover</a></strong><br>
|
||||
</li>
|
||||
</ul>
|
||||
</div>
|
||||
34
docs/dcs/umn/dcs-faq-0326020.html
Normal file
34
docs/dcs/umn/dcs-faq-0326020.html
Normal file
@ -0,0 +1,34 @@
|
||||
<a name="dcs-faq-0326020"></a><a name="dcs-faq-0326020"></a>
|
||||
|
||||
<h1 class="topictitle1">Client and Network Connection</h1>
|
||||
<div id="body8662426"></div>
|
||||
<div>
|
||||
<ul class="ullinks">
|
||||
<li class="ulchildlink"><strong><a href="en-us_topic_0090662012.html">Security Group Configurations</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730001.html">Does DCS Support Public Access?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="en-us_topic_0100698850.html">Does DCS Support Cross-VPC Access?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730004.html">What Should I Do If Access to DCS Fails After Server Disconnects?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730005.html">Why Do Requests Sometimes Time Out in Clients?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730006.html">What Should I Do If an Error Is Returned When I Use the Jedis Connection Pool?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730007.html">Why Is "ERR unknown command" Displayed When I Access a DCS Redis Instance Through a Redis Client?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730008.html">How Do I Access a DCS Redis Instance Through Redis Desktop Manager?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730009.html">What If "ERR Unsupported CONFIG subcommand" is Displayed in SpringCloud?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730010.html">How Do I Troubleshoot Redis Connection Failures?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730011.html">What Should Be Noted When Using Redis for Pub/Sub?</a></strong><br>
|
||||
</li>
|
||||
</ul>
|
||||
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326019.html">FAQs</a></div>
|
||||
</div>
|
||||
</div>
|
||||
54
docs/dcs/umn/dcs-faq-0326021.html
Normal file
54
docs/dcs/umn/dcs-faq-0326021.html
Normal file
@ -0,0 +1,54 @@
|
||||
<a name="dcs-faq-0326021"></a><a name="dcs-faq-0326021"></a>
|
||||
|
||||
<h1 class="topictitle1">Redis Usage</h1>
|
||||
<div id="body8662426"></div>
|
||||
<div>
|
||||
<ul class="ullinks">
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730012.html">Why Is CPU Usage of a DCS Redis Instance 100%?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730013.html">Can I Change the VPC and Subnet for a DCS Redis Instance?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730014.html">Why Aren't Security Groups Configured for DCS Redis 4.0 and 5.0 Instances?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730015.html">Do DCS Redis Instances Limit the Size of a Key or Value?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730017.html">Can I Obtain the Addresses of the Nodes in a Cluster DCS Redis Instance?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730018.html">Why Is Available Memory of a DCS Redis 3.0 Instance Smaller Than Instance Cache Size?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730019.html">Does DCS for Redis Support Multiple Databases?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730020.html">Does DCS for Redis Support Redis Clusters?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730021.html">Does DCS for Redis Support Sentinel?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730022.html">What Is the Default Data Eviction Policy?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730023.html">What Should I Do If an Error Occurs in Redis Exporter?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730024.html">Why Is Memory Usage More Than 100%?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730025.html">Why Is Redisson Distributed Lock Not Supported by DCS Proxy Cluster Redis 3.0 Instances?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730026.html">Can I Customize or Change the Port for Accessing a DCS Instance?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730027.html">Can I Modify the Connection Addresses for Accessing a DCS Instance?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730029.html">Does DCS Support Cross-AZ Deployment?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730030.html">Why Does It Take a Long Time to Start a Cluster DCS Instance?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730032.html">Does DCS for Redis Provide Backend Management Software?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730033.html">Why Is Memory of a DCS Redis Instance Used Up by Just a Few Keys?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730034.html">Can I Recover Data from Deleted DCS Instances?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-210223001.html">Why Is "Error in execution" Returned When I Access Redis?</a></strong><br>
|
||||
</li>
|
||||
</ul>
|
||||
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326019.html">FAQs</a></div>
|
||||
</div>
|
||||
</div>
|
||||
22
docs/dcs/umn/dcs-faq-0326022.html
Normal file
22
docs/dcs/umn/dcs-faq-0326022.html
Normal file
@ -0,0 +1,22 @@
|
||||
<a name="dcs-faq-0326022"></a><a name="dcs-faq-0326022"></a>
|
||||
|
||||
<h1 class="topictitle1">Instance Scaling and Upgrade</h1>
|
||||
<div id="body8662426"></div>
|
||||
<div>
|
||||
<ul class="ullinks">
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730043.html">Can DCS Redis Instances Be Upgraded, for Example, from Redis 3.0 to Redis 4.0 or 5.0?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730044.html">Are Services Interrupted If Maintenance is Performed During the Maintenance Time Window?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730045.html">Are Instance Resources Affected During Specification Modification?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730047.html">Are Services Interrupted During Specification Modification?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730048.html">Why Can't I Modify Specifications for a DCS Redis Instance?</a></strong><br>
|
||||
</li>
|
||||
</ul>
|
||||
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326019.html">FAQs</a></div>
|
||||
</div>
|
||||
</div>
|
||||
18
docs/dcs/umn/dcs-faq-0326023.html
Normal file
18
docs/dcs/umn/dcs-faq-0326023.html
Normal file
@ -0,0 +1,18 @@
|
||||
<a name="dcs-faq-0326023"></a><a name="dcs-faq-0326023"></a>
|
||||
|
||||
<h1 class="topictitle1">Monitoring and Alarm</h1>
|
||||
<div id="body8662426"></div>
|
||||
<div>
|
||||
<ul class="ullinks">
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730049.html">Does Redis Support Command Audits?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730050.html">What Should I Do If the Monitoring Data of a DCS Redis Instance Is Abnormal?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730052.html">Why Is Used Memory Greater Than Available Memory?</a></strong><br>
|
||||
</li>
|
||||
</ul>
|
||||
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326019.html">FAQs</a></div>
|
||||
</div>
|
||||
</div>
|
||||
20
docs/dcs/umn/dcs-faq-0326024.html
Normal file
20
docs/dcs/umn/dcs-faq-0326024.html
Normal file
@ -0,0 +1,20 @@
|
||||
<a name="dcs-faq-0326024"></a><a name="dcs-faq-0326024"></a>
|
||||
|
||||
<h1 class="topictitle1">Data Backup, Export, and Migration</h1>
|
||||
<div id="body8662426"></div>
|
||||
<div>
|
||||
<ul class="ullinks">
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730053.html">How Do I Export DCS Redis Instance Data?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730054.html">Can I Export Backup Data of DCS Redis Instances to RDB Files Using the Console?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-faq-0730057.html">Does DCS Support Data Persistence?</a></strong><br>
|
||||
</li>
|
||||
<li class="ulchildlink"><strong><a href="dcs-migration-090626001.html">Online Migration with Rump</a></strong><br>
|
||||
</li>
|
||||
</ul>
|
||||
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326019.html">FAQs</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730001.html
Normal file
11
docs/dcs/umn/dcs-faq-0730001.html
Normal file
@ -0,0 +1,11 @@
|
||||
<a name="dcs-faq-0730001"></a><a name="dcs-faq-0730001"></a>
|
||||
|
||||
<h1 class="topictitle1">Does DCS Support Public Access?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730001__p151602565397">No. DCS instances cannot be access at their EIPs over public networks. To ensure security, the ECS that serves as a client and the DCS instance that the client will access must belong to the same VPC.</p>
|
||||
<p id="dcs-faq-0730001__p938602954013">In the application development and debugging phase, you can also use an SSH agent to access DCS instances in the local environment.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326020.html">Client and Network Connection</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730004.html
Normal file
11
docs/dcs/umn/dcs-faq-0730004.html
Normal file
@ -0,0 +1,11 @@
|
||||
<a name="dcs-faq-0730004"></a><a name="dcs-faq-0730004"></a>
|
||||
|
||||
<h1 class="topictitle1">What Should I Do If Access to DCS Fails After Server Disconnects?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730004__en-us_topic_0152099099_p01641047144110">Analysis: If persistent connections ("pconnect" in Redis terminology) or connection pooling is used and connections are closed after being used for connecting to DCS instances, errors will be returned at attempts to reuse the connections.</p>
|
||||
<p id="dcs-faq-0730004__en-us_topic_0152099099_p67601221172119">Solution: When using pconnect or connection pooling, do not close the connection after the end of a request. If the connection is dropped, re-establish it.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326020.html">Client and Network Connection</a></div>
|
||||
</div>
|
||||
</div>
|
||||
12
docs/dcs/umn/dcs-faq-0730005.html
Normal file
12
docs/dcs/umn/dcs-faq-0730005.html
Normal file
@ -0,0 +1,12 @@
|
||||
<a name="dcs-faq-0730005"></a><a name="dcs-faq-0730005"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Do Requests Sometimes Time Out in Clients?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730005__en-us_topic_0152099099_p981859161814">Occasional timeout errors are normal because of network connectivity and client timeout configurations.</p>
|
||||
<p id="dcs-faq-0730005__en-us_topic_0152099099_p253031016162">You are advised to include reconnection operations into your service code to avoid service failure if a single request fails.</p>
|
||||
<p id="dcs-faq-0730005__en-us_topic_0152099099_p1453020105168">If timeout errors occur frequently, contact O&M personnel.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326020.html">Client and Network Connection</a></div>
|
||||
</div>
|
||||
</div>
|
||||
43
docs/dcs/umn/dcs-faq-0730006.html
Normal file
43
docs/dcs/umn/dcs-faq-0730006.html
Normal file
@ -0,0 +1,43 @@
|
||||
<a name="dcs-faq-0730006"></a><a name="dcs-faq-0730006"></a>
|
||||
|
||||
<h1 class="topictitle1">What Should I Do If an Error Is Returned When I Use the Jedis Connection Pool?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730006__en-us_topic_0152099099_p1038812015818">The error message that will possibly be displayed when you <span class="keyword" id="dcs-faq-0730006__keyword39817314147">use the Jedis connection pool</span> is as follows:</p>
|
||||
<pre class="screen" id="dcs-faq-0730006__en-us_topic_0152099099_screen2398182394217">redis.clients.jedis.exceptions.JedisConnectionException: Could not get a resource from the pool</pre>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p129321946103813">If this error message is displayed, check whether your instance is running properly. If it is running properly, perform the following checks:</p>
|
||||
<ol id="dcs-faq-0730006__en-us_topic_0152099099_ol980141914912"><li id="dcs-faq-0730006__en-us_topic_0152099099_li10802819590"><span>Network</span><p><ol type="a" id="dcs-faq-0730006__en-us_topic_0152099099_ol4963821184719"><li id="dcs-faq-0730006__en-us_topic_0152099099_li3963182119479">Check the IP address configurations.<p id="dcs-faq-0730006__en-us_topic_0152099099_p173211526174712"><a name="dcs-faq-0730006__en-us_topic_0152099099_li3963182119479"></a><a name="en-us_topic_0152099099_li3963182119479"></a>Check whether the IP address configured on the <span class="keyword" id="dcs-faq-0730006__keyword324316961418">Jedis client</span> is the same as the subnet address configured for your DCS instance. </p>
|
||||
</li><li id="dcs-faq-0730006__en-us_topic_0152099099_li99631217478">Test the network.<p id="dcs-faq-0730006__en-us_topic_0152099099_p113161961483"><a name="dcs-faq-0730006__en-us_topic_0152099099_li99631217478"></a><a name="en-us_topic_0152099099_li99631217478"></a>Use the ping command and telnet on the client to test the network.</p>
|
||||
<ul id="dcs-faq-0730006__en-us_topic_0152099099_ul97951811705"><li id="dcs-faq-0730006__en-us_topic_0152099099_li6637143813114">If the network cannot be pinged:<p id="dcs-faq-0730006__p8645128191212"><a name="dcs-faq-0730006__en-us_topic_0152099099_li6637143813114"></a><a name="en-us_topic_0152099099_li6637143813114"></a>For intra-VPC access to a DCS Redis 3.0 instance, ensure that the client and your DCS instance belong to the same VPC and security group, or the security group of your DCS instance allows access through port 6379. For details, see <a href="en-us_topic_0090662012.html">Security Group Configurations</a>.</p>
|
||||
</li><li id="dcs-faq-0730006__en-us_topic_0152099099_li1799555071112">If the IP address can be pinged but telnet failed, restart your instance. If the problem persists after the restart, contact technical support.</li></ul>
|
||||
</li></ol>
|
||||
</p></li><li id="dcs-faq-0730006__en-us_topic_0152099099_li63411545691"><span>Check the number of connections.</span><p><p id="dcs-faq-0730006__en-us_topic_0152099099_p1594544203317">Check whether the number of established network connections exceeds the upper limit configured for the Jedis connection pool. If the number of established connections approaches the configured upper limit, restart the DCS service and check whether the problem persists. If the number of established connections is far below the upper limit, continue with the following checks.</p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p515384944111">In Unix or Linux, run the following command to query the number of established network connections:</p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p19169838112219"><strong id="dcs-faq-0730006__en-us_topic_0152099099_b0121205511435">netstat -an | grep 6379 | grep ESTABLISHED | wc -l</strong></p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p14884115514418">In Windows, run the following command to query the number of established network connections:</p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p13561849175510"><strong id="dcs-faq-0730006__en-us_topic_0152099099_b2037082414429">netstat -an | find "6379" | find "ESTABLISHED" /C</strong></p>
|
||||
</p></li><li id="dcs-faq-0730006__en-us_topic_0152099099_li1283731212108"><span>Check the JedisPool code.</span><p><p id="dcs-faq-0730006__en-us_topic_0152099099_p172620265618">If the number of established connections approaches the upper limit, determine whether the problem is caused by service concurrency or incorrect usage of JedisPool.</p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p87131344163913">When using JedisPool, you must call <strong id="dcs-faq-0730006__b181141746121417">jedisPool.returnResource()</strong> or <strong id="dcs-faq-0730006__b811415461149">jedis.close()</strong> (recommended) to release the resources after you call <strong id="dcs-faq-0730006__b311594631414">jedisPool.getResource()</strong>.</p>
|
||||
</p></li><li id="dcs-faq-0730006__en-us_topic_0152099099_li7328193913107"><span>Check the number of <span class="keyword" id="dcs-faq-0730006__keyword3174204712145">TIME_WAIT</span> connections.</span><p><p id="dcs-faq-0730006__en-us_topic_0152099099_p192786914011">Run the <strong id="dcs-faq-0730006__b289214488143">ss -s</strong> command to check whether there are too many <strong id="dcs-faq-0730006__b08932048141418">TIME_WAIT</strong> connections on the client.</p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p16614112484920"><span><img id="dcs-faq-0730006__en-us_topic_0152099099_image20133830143115" src="en-us_image_0266315615.png"></span></p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p1886034974910">If there are too many <strong id="dcs-faq-0730006__b177655506149">TIME_WAIT</strong> connections, modify the kernel parameters by running the <strong id="dcs-faq-0730006__b3766050111419">/etc/sysctl.conf</strong> command as follows:</p>
|
||||
<pre class="screen" id="dcs-faq-0730006__en-us_topic_0152099099_screen1874851017377">##Uses cookies to prevent some SYN flood attacks when the SYN waiting queue overflows.
|
||||
net.ipv4.tcp_syncookies = 1
|
||||
##Reuses <strong id="dcs-faq-0730006__b12585125411141">TIME_WAIT</strong> sockets for new TCP connections.
|
||||
net.ipv4.tcp_tw_reuse = 1
|
||||
##Enables quick reclamation of <strong id="dcs-faq-0730006__b1937519562145">TIME_WAIT</strong> sockets in TCP connections.
|
||||
net.ipv4.tcp_tw_recycle = 1
|
||||
##Modifies the default timeout time of the system.
|
||||
net.ipv4.tcp_fin_timeout = 30</pre>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p1699145417363">After the modification, run the <strong id="dcs-faq-0730006__b19280508159">/sbin/sysctl -p</strong> command for the modification to take effect.</p>
|
||||
</p></li><li id="dcs-faq-0730006__en-us_topic_0152099099_li0857976116"><span>If the problem persists after you perform the preceding checks, perform the following steps.</span><p><p id="dcs-faq-0730006__en-us_topic_0152099099_p1231215485513">Capture packets and send packet files along with the time and description of the exception to technical support for analysis.</p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p897110554515">Run the following command to capture packets:</p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p31223103512"><strong id="dcs-faq-0730006__en-us_topic_0152099099_b11679160115217">tcpdump -i eth0 tcp and port 6379 -n -nn -s 74 -w dump.pcap</strong></p>
|
||||
<p id="dcs-faq-0730006__en-us_topic_0152099099_p87821548142">In Windows, you can also install the Wireshark tool to capture packets.</p>
|
||||
<div class="note" id="dcs-faq-0730006__en-us_topic_0152099099_note1271424122719"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="dcs-faq-0730006__en-us_topic_0152099099_p98189192712">Replace the NIC name to the actual one.</p>
|
||||
</div></div>
|
||||
</p></li></ol>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326020.html">Client and Network Connection</a></div>
|
||||
</div>
|
||||
</div>
|
||||
16
docs/dcs/umn/dcs-faq-0730007.html
Normal file
16
docs/dcs/umn/dcs-faq-0730007.html
Normal file
@ -0,0 +1,16 @@
|
||||
<a name="dcs-faq-0730007"></a><a name="dcs-faq-0730007"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Is "ERR unknown command" Displayed When I Access a DCS Redis Instance Through a Redis Client?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730007__en-us_topic_0152099099_p196719695311">The possible causes are as follows:</p>
|
||||
<ol id="dcs-faq-0730007__en-us_topic_0152099099_ol02571317120"><li id="dcs-faq-0730007__en-us_topic_0152099099_li32514137117">The command is spelled incorrectly.<p id="dcs-faq-0730007__en-us_topic_0152099099_p1793654714211"><a name="dcs-faq-0730007__en-us_topic_0152099099_li32514137117"></a><a name="en-us_topic_0152099099_li32514137117"></a>As shown in the following figure, the error message is returned because the correct command for deleting a string should be <strong id="dcs-faq-0730007__b11197171545219">del</strong>.</p>
|
||||
<p id="dcs-faq-0730007__en-us_topic_0152099099_p12522551218"><span><img id="dcs-faq-0730007__en-us_topic_0152099099_image58393378210" src="en-us_image_0266315616.png"></span></p>
|
||||
</li><li id="dcs-faq-0730007__en-us_topic_0152099099_li225141316111">A command available in a higher Redis version is run in a lower Redis version.<p id="dcs-faq-0730007__en-us_topic_0152099099_p837784381913"><a name="dcs-faq-0730007__en-us_topic_0152099099_li225141316111"></a><a name="en-us_topic_0152099099_li225141316111"></a>As shown in the following figure, the error message is returned because a stream command (available in Redis 5.0) is run in Redis 3.0.</p>
|
||||
<p id="dcs-faq-0730007__en-us_topic_0152099099_p667431195"><span><img id="dcs-faq-0730007__en-us_topic_0152099099_image164815412710" src="en-us_image_0266315617.png"></span></p>
|
||||
</li><li id="dcs-faq-0730007__en-us_topic_0152099099_li525713517">Some commands are disabled.<p id="dcs-faq-0730007__en-us_topic_0152099099_p4666647102019"><a name="dcs-faq-0730007__en-us_topic_0152099099_li525713517"></a><a name="en-us_topic_0152099099_li525713517"></a>DCS Redis instance interfaces are fully compatible with the open-source Redis in terms of data access. However, for ease of use and security purposes, some operations cannot be initiated through Redis clients. For details about disabled commands, see <a href="dcs-pd-200312003.html">Command Compatibility</a>.</p>
|
||||
</li></ol>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326020.html">Client and Network Connection</a></div>
|
||||
</div>
|
||||
</div>
|
||||
15
docs/dcs/umn/dcs-faq-0730008.html
Normal file
15
docs/dcs/umn/dcs-faq-0730008.html
Normal file
@ -0,0 +1,15 @@
|
||||
<a name="dcs-faq-0730008"></a><a name="dcs-faq-0730008"></a>
|
||||
|
||||
<h1 class="topictitle1">How Do I Access a DCS Redis Instance Through Redis Desktop Manager?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730008__en-us_topic_0152099099_p412722720489">You can access a DCS Redis instance through the Redis Desktop Manager within a VPC.</p>
|
||||
<ol id="dcs-faq-0730008__en-us_topic_0152099099_ol107224124413"><li id="dcs-faq-0730008__en-us_topic_0152099099_li137824154420">Enter the address, port number (6379), and authentication password of the DCS instance you want to access.</li><li id="dcs-faq-0730008__en-us_topic_0152099099_li1910315304440">Click <strong id="dcs-faq-0730008__b129991046205816">Test Connection</strong>.<p id="dcs-faq-0730008__en-us_topic_0152099099_p93523294415">The system displays a success message if the connection is successful.</p>
|
||||
<div class="fignone" id="dcs-faq-0730008__en-us_topic_0152099099_fig1917118510459"><span class="figcap"><b>Figure 1 </b>Accessing a DCS Redis instance through Redis Desktop Manager over the intranet</span><br><span><img id="dcs-faq-0730008__en-us_topic_0152099099_image16136128151012" src="en-us_image_0266315618.png"></span></div>
|
||||
<div class="note" id="dcs-faq-0730008__en-us_topic_0152099099_note699593614451"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="dcs-faq-0730008__en-us_topic_0152099099_p199951336184515">When accessing a cluster DCS instance, the Redis command is run properly, but an error message may display on the left because DCS clusters are based on Codis, which differs from the native Redis in terms of the <strong id="dcs-faq-0730008__b9796125355818">INFO</strong> command output.</p>
|
||||
</div></div>
|
||||
</li></ol>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326020.html">Client and Network Connection</a></div>
|
||||
</div>
|
||||
</div>
|
||||
22
docs/dcs/umn/dcs-faq-0730009.html
Normal file
22
docs/dcs/umn/dcs-faq-0730009.html
Normal file
@ -0,0 +1,22 @@
|
||||
<a name="dcs-faq-0730009"></a><a name="dcs-faq-0730009"></a>
|
||||
|
||||
<h1 class="topictitle1">What If "ERR Unsupported CONFIG subcommand" is Displayed in SpringCloud?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730009__en-us_topic_0152099099_p11422113014583">By using DCS Redis instances, <span class="keyword" id="dcs-faq-0730009__keyword75301593585">Spring Session can implement session sharing</span>. When interconnecting with Spring Cloud, the following error information is displayed:</p>
|
||||
<div class="fignone" id="dcs-faq-0730009__en-us_topic_0152099099_fig1775053516012"><span class="figcap"><b>Figure 1 </b>Spring Cloud error information</span><br><span><img id="dcs-faq-0730009__en-us_topic_0152099099_image20258254115810" src="en-us_image_0266315619.png"></span></div>
|
||||
<p id="dcs-faq-0730009__en-us_topic_0152099099_p3701016105918">For security purposes, DCS does not support the <strong id="dcs-faq-0730009__b28725425920">CONFIG</strong> command initiated by a client. You need to perform the following steps:</p>
|
||||
<ol id="dcs-faq-0730009__en-us_topic_0152099099_ol82491552120"><li id="dcs-faq-0730009__en-us_topic_0152099099_li32480551812">On the DCS console, set the value of the <strong id="dcs-faq-0730009__b7186568598">notify-keyspace-event</strong> parameter to <strong id="dcs-faq-0730009__b17186196125917">Egx</strong> for a DCS Redis instance.</li><li id="dcs-faq-0730009__en-us_topic_0152099099_li924845512118">Add the following content to the XML configuration file of the Spring framework:<p id="dcs-faq-0730009__en-us_topic_0152099099_p2097611571110"><a name="dcs-faq-0730009__en-us_topic_0152099099_li924845512118"></a><a name="en-us_topic_0152099099_li924845512118"></a><util:constant</p>
|
||||
<p id="dcs-faq-0730009__en-us_topic_0152099099_p672110325">static-field="org.springframework.session.data.redis.config.ConfigureRedisAction.NO_OP"/></p>
|
||||
</li><li id="dcs-faq-0730009__en-us_topic_0152099099_li182493557111">Modify the related Spring code. Enable the <strong id="dcs-faq-0730009__b3571493597">ConfigureRedisAction.NO_OP</strong> bean component to forbid a client to invoke the <strong id="dcs-faq-0730009__b195816965917">CONFIG</strong> command.<p id="dcs-faq-0730009__en-us_topic_0152099099_p161361613726">@Bean</p>
|
||||
<p id="dcs-faq-0730009__en-us_topic_0152099099_p1913611137218">public static ConfigureRedisAction configureRedisAction() {</p>
|
||||
<p id="dcs-faq-0730009__en-us_topic_0152099099_p4136121312218">return ConfigureRedisAction.NO_OP;</p>
|
||||
<p id="dcs-faq-0730009__en-us_topic_0152099099_p8136111317210">}</p>
|
||||
</li></ol>
|
||||
<p id="dcs-faq-0730009__en-us_topic_0152099099_p319234318111">For more information, see the <a href="https://docs.spring.io/spring-session/docs/current/api/" target="_blank" rel="noopener noreferrer">Spring Session Documentation</a>.</p>
|
||||
<div class="notice" id="dcs-faq-0730009__en-us_topic_0152099099_note139026388342"><span class="noticetitle"><img src="public_sys-resources/notice_3.0-en-us.png"> </span><div class="noticebody"><p id="dcs-faq-0730009__en-us_topic_0152099099_p990233883412">Session sharing is supported only by <strong id="dcs-faq-0730009__b1487021465913">single-node</strong> and <strong id="dcs-faq-0730009__b12870191425910">master/standby</strong> DCS Redis instances, but not by cluster DCS Redis instances.</p>
|
||||
</div></div>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326020.html">Client and Network Connection</a></div>
|
||||
</div>
|
||||
</div>
|
||||
24
docs/dcs/umn/dcs-faq-0730010.html
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24
docs/dcs/umn/dcs-faq-0730010.html
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@ -0,0 +1,24 @@
|
||||
<a name="dcs-faq-0730010"></a><a name="dcs-faq-0730010"></a>
|
||||
|
||||
<h1 class="topictitle1">How Do I Troubleshoot Redis Connection Failures?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730010__en-us_topic_0152099099_p1220253901312"><strong id="dcs-faq-0730010__b193371534125919">Preliminary checks:</strong></p>
|
||||
<ul id="dcs-faq-0730010__en-us_topic_0152099099_ul1046719202222"><li id="dcs-faq-0730010__en-us_topic_0152099099_li11467620102213">Check the connection address.<p id="dcs-faq-0730010__en-us_topic_0152099099_p2679175422217"><a name="dcs-faq-0730010__en-us_topic_0152099099_li11467620102213"></a><a name="en-us_topic_0152099099_li11467620102213"></a>Obtain the connection address from the instance basic information page on the DCS console.</p>
|
||||
</li><li id="dcs-faq-0730010__en-us_topic_0152099099_li10467152082214">Check the instance password.<p id="dcs-faq-0730010__en-us_topic_0152099099_p191321182317"><a name="dcs-faq-0730010__en-us_topic_0152099099_li10467152082214"></a><a name="en-us_topic_0152099099_li10467152082214"></a>If the instance password is incorrect, the port can still be accessed but the authentication will fail.</p>
|
||||
</li><li id="dcs-faq-0730010__en-us_topic_0152099099_li204675203221">Check the port.<p id="dcs-faq-0730010__en-us_topic_0152099099_p1440165418233"><a name="dcs-faq-0730010__en-us_topic_0152099099_li204675203221"></a><a name="en-us_topic_0152099099_li204675203221"></a>Port 6379 is the default port used in intra-VPC access to a DCS Redis instance.</p>
|
||||
</li><li id="dcs-faq-0730010__en-us_topic_0152099099_li1017384662415">Check if the maximum bandwidth has been reached.<p id="dcs-faq-0730010__en-us_topic_0152099099_p1797526102510"><a name="dcs-faq-0730010__en-us_topic_0152099099_li1017384662415"></a><a name="en-us_topic_0152099099_li1017384662415"></a>If the bandwidth reaches the maximum bandwidth for the corresponding instance specifications, Redis connections may time out.</p>
|
||||
</li><li id="dcs-faq-0730010__en-us_topic_0152099099_li1846772016228">For a DCS Redis 3.0 instance, check the inbound access rules of the security group.<p id="dcs-faq-0730010__en-us_topic_0152099099_p14645112182815"><a name="dcs-faq-0730010__en-us_topic_0152099099_li1846772016228"></a><a name="en-us_topic_0152099099_li1846772016228"></a>Intra-VPC access: If the Redis client and the Redis instance are bound with different security groups, allow inbound access over port 6379 for the security group of the instance.</p>
|
||||
<p id="dcs-faq-0730010__p14803202620398">For details, see <a href="en-us_topic_0090662012.html">Security Group Configurations</a>.</p>
|
||||
</li><li id="dcs-faq-0730010__li2046822714264">For a DCS Redis 4.0 or 5.0 instance, check the whitelist configuration.<p id="dcs-faq-0730010__p86935385270"><a name="dcs-faq-0730010__li2046822714264"></a><a name="li2046822714264"></a>If the instance has a whitelist, ensure that the client IP address is included in the whitelist. Otherwise, the connection will fail.</p>
|
||||
<p id="dcs-faq-0730010__p1429974202718">For details, see <a href="dcs-ug-190812001.html">Managing IP Address Whitelist</a>.</p>
|
||||
<p id="dcs-faq-0730010__p13299216102715">If the client IP address has changed, add the new IP address to the whitelist.</p>
|
||||
</li><li id="dcs-faq-0730010__en-us_topic_0152099099_li10464192019419">Check the configuration parameter <strong id="dcs-faq-0730010__b13215165255914">notify-keyspace-events</strong>.<p id="dcs-faq-0730010__en-us_topic_0152099099_p66120341344">Set <strong id="dcs-faq-0730010__b1961115532594">notify-keyspace-events</strong> to <strong id="dcs-faq-0730010__b1761113531598">Egx</strong>.</p>
|
||||
</li></ul>
|
||||
<p id="dcs-faq-0730010__en-us_topic_0152099099_p1253519119149"><strong id="dcs-faq-0730010__b93118556595">Further checks:</strong></p>
|
||||
<ul id="dcs-faq-0730010__en-us_topic_0152099099_ul164841037163114"><li id="dcs-faq-0730010__en-us_topic_0152099099_li17484143710315">Jedis connection pool error</li><li id="dcs-faq-0730010__en-us_topic_0152099099_li2049319151671">Error "Read timed out" or "Could not get a resource from the pool"<p id="dcs-faq-0730010__en-us_topic_0152099099_p34261161283"><a name="dcs-faq-0730010__en-us_topic_0152099099_li2049319151671"></a><a name="en-us_topic_0152099099_li2049319151671"></a>Check if the <strong id="dcs-faq-0730010__b1691313590595">KEYS</strong> command has been used. This command consumes a lot of resources and can easily block Redis. Instead, use the <strong id="dcs-faq-0730010__b15168419013">SCAN</strong> command and avoid executing the command frequently.</p>
|
||||
</li></ul>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326020.html">Client and Network Connection</a></div>
|
||||
</div>
|
||||
</div>
|
||||
14
docs/dcs/umn/dcs-faq-0730011.html
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14
docs/dcs/umn/dcs-faq-0730011.html
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@ -0,0 +1,14 @@
|
||||
<a name="dcs-faq-0730011"></a><a name="dcs-faq-0730011"></a>
|
||||
|
||||
<h1 class="topictitle1">What Should Be Noted When Using Redis for Pub/Sub?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730011__en-us_topic_0152099099_p1016844615317">Pay attention to the following issues when using <span class="keyword" id="dcs-faq-0730011__keyword164002810011">Redis for pub/sub</span>:</p>
|
||||
<ul id="dcs-faq-0730011__en-us_topic_0152099099_ul198440511594"><li id="dcs-faq-0730011__en-us_topic_0152099099_li984415575911">Your client must process messages in a timely manner.<p id="dcs-faq-0730011__en-us_topic_0152099099_p21880373116"><a name="dcs-faq-0730011__en-us_topic_0152099099_li984415575911"></a><a name="en-us_topic_0152099099_li984415575911"></a>Your client subscribes to a channel. If it does not receive messages in a timely manner, DCS instance messages may be overstocked. If the size of accumulated messages reaches the threshold (32 MB by default) or remains at a certain level (8 MB by default) for a certain period of time (1 minute by default), your client will be automatically disconnected to prevent server memory exhaustion.</p>
|
||||
</li><li id="dcs-faq-0730011__en-us_topic_0152099099_li178449595911">Your client must support connection re-establishment in case of disconnection.<p id="dcs-faq-0730011__en-us_topic_0152099099_p96981571315"><a name="dcs-faq-0730011__en-us_topic_0152099099_li178449595911"></a><a name="en-us_topic_0152099099_li178449595911"></a>In the event of a disconnection, you need to run the <strong id="dcs-faq-0730011__b639911154011">subscribe </strong>or <strong id="dcs-faq-0730011__b24044151804">psubscribe</strong> command on your client to subscribe to a channel again. Otherwise, your client cannot receive messages.</p>
|
||||
</li><li id="dcs-faq-0730011__en-us_topic_0152099099_li208447517592">Do not use pub/sub in scenarios with high message reliability requirements.<p id="dcs-faq-0730011__en-us_topic_0152099099_p1950115381025"><a name="dcs-faq-0730011__en-us_topic_0152099099_li208447517592"></a><a name="en-us_topic_0152099099_li208447517592"></a>The Redis pub/sub is not a reliable messaging system. Messages that are not retrieved will be discarded when your client is disconnected or a master/standby switchover occurs.</p>
|
||||
</li></ul>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326020.html">Client and Network Connection</a></div>
|
||||
</div>
|
||||
</div>
|
||||
13
docs/dcs/umn/dcs-faq-0730012.html
Normal file
13
docs/dcs/umn/dcs-faq-0730012.html
Normal file
@ -0,0 +1,13 @@
|
||||
<a name="dcs-faq-0730012"></a><a name="dcs-faq-0730012"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Is CPU Usage of a DCS Redis Instance 100%?</h1>
|
||||
<div id="body1596093268949"><ul id="dcs-faq-0730012__en-us_topic_0152099097_ul16254164916516"><li id="dcs-faq-0730012__en-us_topic_0152099097_li17255114919516">Possible cause 1:<p id="dcs-faq-0730012__en-us_topic_0152099097_p11315175219510"><a name="dcs-faq-0730012__en-us_topic_0152099097_li17255114919516"></a><a name="en-us_topic_0152099097_li17255114919516"></a>The service QPS is so high that the CPU usage spikes to 100%.</p>
|
||||
</li></ul>
|
||||
<ul id="dcs-faq-0730012__en-us_topic_0152099097_ul1025594945113"><li id="dcs-faq-0730012__en-us_topic_0152099097_li725544919512">Possible cause 2:<p id="dcs-faq-0730012__en-us_topic_0152099097_p35242546516"><a name="dcs-faq-0730012__en-us_topic_0152099097_li725544919512"></a><a name="en-us_topic_0152099097_li725544919512"></a>You have run commands that consume a lot of resources, such as <strong id="dcs-faq-0730012__b16727328107">KEYS</strong>. This will make CPU usage spike and can easily trigger a master/standby switchover.</p>
|
||||
</li></ul>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
10
docs/dcs/umn/dcs-faq-0730013.html
Normal file
10
docs/dcs/umn/dcs-faq-0730013.html
Normal file
@ -0,0 +1,10 @@
|
||||
<a name="dcs-faq-0730013"></a><a name="dcs-faq-0730013"></a>
|
||||
|
||||
<h1 class="topictitle1">Can I Change the VPC and Subnet for a DCS Redis Instance?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730013__en-us_topic_0152099097_p344291218392">No. Once an instance is created, its VPC and subnet cannot be changed. If you want to use a different set of VPC and subnet, create a same instance and specify a desired set of VPC and subnet. After the new instance is created, you can migrate data from the old instance to the new instance by following the <a href="dcs-ug-0312035.html">data migration instructions</a>.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
12
docs/dcs/umn/dcs-faq-0730014.html
Normal file
12
docs/dcs/umn/dcs-faq-0730014.html
Normal file
@ -0,0 +1,12 @@
|
||||
<a name="dcs-faq-0730014"></a><a name="dcs-faq-0730014"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Aren't Security Groups Configured for DCS Redis 4.0 and 5.0 Instances?</h1>
|
||||
<div id="body1596093268949"><p id="dcs-faq-0730014__en-us_topic_0152099097_p16123134244116">Currently, DCS Redis 4.0 and Redis 5.0 instances use VPC endpoints and do not support security groups. You can configure whitelists instead. For details, see <a href="dcs-ug-190812001.html">Managing IP Address Whitelist</a>.</p>
|
||||
<p id="dcs-faq-0730014__p167460299191">To allow access only from specific IP addresses to a DCS Redis 4.0 or 5.0 instance, add the IP addresses to the instance whitelist.</p>
|
||||
<p id="dcs-faq-0730014__p8907193444015">If no whitelists are added to the instance whitelist or the whitelist function is disabled, all IP addresses that can communicate with the VPC can access the instance.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
13
docs/dcs/umn/dcs-faq-0730015.html
Normal file
13
docs/dcs/umn/dcs-faq-0730015.html
Normal file
@ -0,0 +1,13 @@
|
||||
<a name="dcs-faq-0730015"></a><a name="dcs-faq-0730015"></a>
|
||||
|
||||
<h1 class="topictitle1">Do DCS Redis Instances Limit the Size of a Key or Value?</h1>
|
||||
<div id="body1596093268949"><ul id="dcs-faq-0730015__en-us_topic_0152099097_ul5399430122814"><li id="dcs-faq-0730015__en-us_topic_0152099097_li18254143043312">The maximum allowed size of a key is 512 MB.<p id="dcs-faq-0730015__en-us_topic_0152099097_p5100103293310"><a name="dcs-faq-0730015__en-us_topic_0152099097_li18254143043312"></a><a name="en-us_topic_0152099097_li18254143043312"></a>To reduce memory usage and facilitate key query, ensure that each key does not exceed 1 KB.</p>
|
||||
</li><li id="dcs-faq-0730015__en-us_topic_0152099097_li103995308287">The maximum allowed size of a string is 512 MB.</li><li id="dcs-faq-0730015__en-us_topic_0152099097_li639963013287">The maximum allowed size of a Set, List, or Hash is 512 MB.<p id="dcs-faq-0730015__en-us_topic_0152099097_p5795336311"><a name="dcs-faq-0730015__en-us_topic_0152099097_li639963013287"></a><a name="en-us_topic_0152099097_li639963013287"></a>In essence, a Set is a collection of Strings; a List is a list of Strings; a Hash contains mappings between string fields and string values.</p>
|
||||
</li></ul>
|
||||
<p id="dcs-faq-0730015__en-us_topic_0152099097_p316012465475">Prevent the client from constantly writing large values in Redis. Otherwise, network transmission efficiency will be lowered and the Redis server would take a longer time to process commands, resulting in higher latency.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
14
docs/dcs/umn/dcs-faq-0730017.html
Normal file
14
docs/dcs/umn/dcs-faq-0730017.html
Normal file
@ -0,0 +1,14 @@
|
||||
<a name="dcs-faq-0730017"></a><a name="dcs-faq-0730017"></a>
|
||||
|
||||
<h1 class="topictitle1">Can I Obtain the Addresses of the Nodes in a Cluster DCS Redis Instance?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730017__en-us_topic_0152099097_p1483584313321">Cluster DCS Redis 3.0 instances (Proxy Cluster type) are used in the same way that you use single-node or master/standby instances. You do not need to know the backend node addresses.</p>
|
||||
<p id="dcs-faq-0730017__en-us_topic_0152099097_p1835134343213">For a cluster DCS Redis 4.0 or 5.0 instance (Redis Cluster type), run the <strong id="dcs-faq-0730017__b16188355307">CLUSTER NODES</strong> command to obtain node addresses:</p>
|
||||
<p id="dcs-faq-0730017__en-us_topic_0152099097_p64034338434"><strong id="dcs-faq-0730017__en-us_topic_0152099097_b1740393319431">redis-cli -h <em id="dcs-faq-0730017__en-us_topic_0152099097_i174031933184315">{redis_address}</em> -p <em id="dcs-faq-0730017__en-us_topic_0152099097_i44036333433">{redis_port}</em> -a <em id="dcs-faq-0730017__en-us_topic_0152099097_i184031833204314">{redis_password}</em> cluster nodes</strong></p>
|
||||
<p id="dcs-faq-0730017__en-us_topic_0152099097_p12403163316433">In the output similar to the following, obtain the IP addresses and port numbers of all the master nodes.</p>
|
||||
<p id="dcs-faq-0730017__en-us_topic_0152099097_p9149163917382"><span><img id="dcs-faq-0730017__en-us_topic_0152099097_image19820346211" src="en-us_image_0266316213.png"></span></p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
10
docs/dcs/umn/dcs-faq-0730018.html
Normal file
10
docs/dcs/umn/dcs-faq-0730018.html
Normal file
@ -0,0 +1,10 @@
|
||||
<a name="dcs-faq-0730018"></a><a name="dcs-faq-0730018"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Is Available Memory of a DCS Redis 3.0 Instance Smaller Than Instance Cache Size?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730018__en-us_topic_0152099097_p1131455111168">DCS Redis 3.0 instances are deployed on VMs and some memory is reserved for system overheads.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730019.html
Normal file
11
docs/dcs/umn/dcs-faq-0730019.html
Normal file
@ -0,0 +1,11 @@
|
||||
<a name="dcs-faq-0730019"></a><a name="dcs-faq-0730019"></a>
|
||||
|
||||
<h1 class="topictitle1">Does DCS for Redis Support Multiple Databases?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730019__en-us_topic_0152099097_p8060118">Both single-node and master/standby <span class="keyword" id="dcs-faq-0730019__keyword1446512212151">DCS Redis instances support multiple databases</span>. By default, single-node and master/standby DCS instances can read and write data in 256 databases (databases numbering 0–255).</p>
|
||||
<p id="dcs-faq-0730019__en-us_topic_0152099097_p4242154222010">Cluster DCS instances do not support data read/write in multiple databases.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
10
docs/dcs/umn/dcs-faq-0730020.html
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10
docs/dcs/umn/dcs-faq-0730020.html
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|
||||
<a name="dcs-faq-0730020"></a><a name="dcs-faq-0730020"></a>
|
||||
|
||||
<h1 class="topictitle1">Does DCS for Redis Support Redis Clusters?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730020__en-us_topic_0152099097_p725111122119">Yes. DCS for Redis 4.0 and 5.0 support Redis Clusters. DCS for Redis 3.0 supports Proxy Clusters.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730021.html
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11
docs/dcs/umn/dcs-faq-0730021.html
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|
||||
<a name="dcs-faq-0730021"></a><a name="dcs-faq-0730021"></a>
|
||||
|
||||
<h1 class="topictitle1">Does DCS for Redis Support Sentinel?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730021__en-us_topic_0152099097_p047315232012">Yes. Redis Sentinel is supported by DCS for Redis 4.0 and 5.0 and is enabled by default. Sentinel constantly checks if master and replica nodes are running properly. If the master is not running properly, Sentinel starts a failover process and promotes a replica to master.</p>
|
||||
<p id="dcs-faq-0730021__en-us_topic_0152099097_p74691819125910">However, DCS for Redis 3.0 does not support Redis Sentinel. Instead, it uses keepalive to monitor master and replica nodes and to manage failovers.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
16
docs/dcs/umn/dcs-faq-0730022.html
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16
docs/dcs/umn/dcs-faq-0730022.html
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|
||||
<a name="dcs-faq-0730022"></a><a name="dcs-faq-0730022"></a>
|
||||
|
||||
<h1 class="topictitle1">What Is the Default Data Eviction Policy?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730022__en-us_topic_0152099097_p891453012313">Data is evicted from cache based on a user-defined space limit in order to make space for new data. In the current versions of DCS, you can select an eviction policy.</p>
|
||||
<p id="dcs-faq-0730022__en-us_topic_0152099097_p84517544616"><strong id="dcs-faq-0730022__b9531817917">noeviction</strong> is the <span class="keyword" id="dcs-faq-0730022__keyword13587172119">default eviction policy</span> for single-node and master/standby DCS Redis instances. You can change the eviction policy by configuring the instance parameters on the DCS console.</p>
|
||||
<p id="dcs-faq-0730022__en-us_topic_0152099097_p4839017143534"><strong id="dcs-faq-0730022__b131721719919">volatile-lru</strong> is the default eviction policy for cluster DCS Redis instances. To change the eviction policy for cluster instances, contact technical support.</p>
|
||||
<p id="dcs-faq-0730022__en-us_topic_0152099097_p24119933153714">When <strong id="dcs-faq-0730022__b9411301292">maxmemory</strong> is reached, you can select one of the following eight eviction policies:</p>
|
||||
<ul id="dcs-faq-0730022__ul63511053153341"><li id="dcs-faq-0730022__li46713159155023"><strong id="dcs-faq-0730022__b148525218919">noeviction</strong>: When the memory limit is reached, DCS instances return errors to clients and no longer process write requests and other requests that could result in more memory to be used. However, <strong id="dcs-faq-0730022__b23887235114">DEL</strong> and a few more exception requests can continue to be processed.</li><li id="dcs-faq-0730022__li33146435153341"><strong id="dcs-faq-0730022__b12386224217">allkeys-lru</strong>: DCS instances try to evict the least recently used keys first, in order to make space for new data.</li><li id="dcs-faq-0730022__li62982494153346"><strong id="dcs-faq-0730022__b1523412252113">volatile-lru</strong>: DCS instances try to evict the least recently used keys with an expire set first, in order to make space for new data.</li><li id="dcs-faq-0730022__li61473187153348"><strong id="dcs-faq-0730022__b9967425718">allkeys-random</strong>: DCS instances recycle random keys so that new data can be stored.</li><li id="dcs-faq-0730022__li9870151153350"><strong id="dcs-faq-0730022__b15787152616119">volatile-random</strong>: DCS instances evict random keys with an expire set, in order to make space for new data.</li><li id="dcs-faq-0730022__li3073190415343"><strong id="dcs-faq-0730022__b989313618914">volatile-ttl</strong>: DCS instances evict keys with an expire set, and try to evict keys with a shorter time to live (TTL) first, in order to make space for new data.</li><li id="dcs-faq-0730022__li1918134611344"><strong id="dcs-faq-0730022__b188119815917">allkeys-lfu</strong>: DCS instances evict the least frequently used keys from all keys.</li><li id="dcs-faq-0730022__li188701956123617"><strong id="dcs-faq-0730022__b12439131113918">volatile-lfu</strong>: DCS instances evict the least frequently used keys with an <strong id="dcs-faq-0730022__b1944015111698">expire</strong> field from all keys.</li></ul>
|
||||
<div class="note" id="dcs-faq-0730022__en-us_topic_0152099097_note33192730155638"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="dcs-faq-0730022__en-us_topic_0152099097_p30299119155638">If no key can be recycled, <strong id="dcs-faq-0730022__b122631228518">volatile-lru</strong>, <strong id="dcs-faq-0730022__b626410282110">volatile-random</strong>, and <strong id="dcs-faq-0730022__b62641528915">volatile-ttl</strong> are the same as <strong id="dcs-faq-0730022__b1526417284111">noeviction</strong>. For details, see the description of <strong id="dcs-faq-0730022__b42649283119">noeviction</strong>.</p>
|
||||
</div></div>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730023.html
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11
docs/dcs/umn/dcs-faq-0730023.html
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@ -0,0 +1,11 @@
|
||||
<a name="dcs-faq-0730023"></a><a name="dcs-faq-0730023"></a>
|
||||
|
||||
<h1 class="topictitle1">What Should I Do If an Error Occurs in Redis Exporter?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730023__en-us_topic_0152099097_p367417420511">Start the Redis exporter using the CLI. Based on the output, check for errors and troubleshoot accordingly.</p>
|
||||
<p id="dcs-faq-0730023__en-us_topic_0152099097_p17674142145114"><span><img id="dcs-faq-0730023__en-us_topic_0152099097_image267410421514" src="en-us_image_0266316214.jpg"></span></p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
10
docs/dcs/umn/dcs-faq-0730024.html
Normal file
10
docs/dcs/umn/dcs-faq-0730024.html
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@ -0,0 +1,10 @@
|
||||
<a name="dcs-faq-0730024"></a><a name="dcs-faq-0730024"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Is Memory Usage More Than 100%?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730024__en-us_topic_0152099097_p1212493273818">This is normal due to Redis functions (such as master/replica replication and lazyfree). When the memory becomes full, scale up the instance or remove unnecessary data.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
13
docs/dcs/umn/dcs-faq-0730025.html
Normal file
13
docs/dcs/umn/dcs-faq-0730025.html
Normal file
@ -0,0 +1,13 @@
|
||||
<a name="dcs-faq-0730025"></a><a name="dcs-faq-0730025"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Is Redisson Distributed Lock Not Supported by DCS Proxy Cluster Redis 3.0 Instances?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730025__en-us_topic_0152099097_p227692415350">Redisson implements lock acquisition and unlocking in the following process:</p>
|
||||
<ol id="dcs-faq-0730025__en-us_topic_0152099097_ol106890279329"><li id="dcs-faq-0730025__en-us_topic_0152099097_li10690122714325">Redisson lock acquisition and unlocking are implemented by running Lua scripts.</li><li id="dcs-faq-0730025__en-us_topic_0152099097_li13690527103212">During lock acquisition, the <strong id="dcs-faq-0730025__b973819493115">EXISTS</strong>, <strong id="dcs-faq-0730025__b147431491411">HSET</strong>, <strong id="dcs-faq-0730025__b1474319496118">PEXPIRE</strong>, <strong id="dcs-faq-0730025__b574324919119">HEXISTS</strong>, <strong id="dcs-faq-0730025__b18743649813">HINCRBY</strong>, <strong id="dcs-faq-0730025__b37431549912">PEXPIRE</strong>, and <strong id="dcs-faq-0730025__b17441491117">PTTL</strong> commands must be executed in the Lua script.</li><li id="dcs-faq-0730025__en-us_topic_0152099097_li126904275320">During unlocking, the <strong id="dcs-faq-0730025__b6722145010113">EXISTS</strong>, <strong id="dcs-faq-0730025__b472325014114">PUBLISH</strong>, <strong id="dcs-faq-0730025__b1072320501312">HEXISTS</strong>, <strong id="dcs-faq-0730025__b1172313502117">PEXIPRE</strong>, and <strong id="dcs-faq-0730025__b47231850311">DEL</strong> commands must be executed in the Lua script.</li></ol>
|
||||
<p id="dcs-faq-0730025__en-us_topic_0152099097_p82082536353">In a proxy-based cluster, the proxy processes <strong id="dcs-faq-0730025__b86291151212">PUBLISH</strong> and <strong id="dcs-faq-0730025__b5629135120111">SUBSCRIBE</strong> commands and forwards requests to the Redis server. The <strong id="dcs-faq-0730025__b146301851418">PUBLISH</strong> command cannot be executed in the Lua script.</p>
|
||||
<p id="dcs-faq-0730025__en-us_topic_0152099097_p10806319113210">As a result, Proxy Cluster DCS Redis 3.0 instances do not support Redisson distributed locks. To use Redisson, resort to Redis 4.0 or 5.0 instead.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
14
docs/dcs/umn/dcs-faq-0730026.html
Normal file
14
docs/dcs/umn/dcs-faq-0730026.html
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@ -0,0 +1,14 @@
|
||||
<a name="dcs-faq-0730026"></a><a name="dcs-faq-0730026"></a>
|
||||
|
||||
<h1 class="topictitle1">Can I Customize or Change the Port for Accessing a DCS Instance?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730026__p15703171835620">You cannot customize or change the port for accessing a DCS Redis 3.0 instance. You can customize and change the port for accessing a DCS Redis 4.0 or 5.0 instance.</p>
|
||||
<ul id="dcs-faq-0730026__en-us_topic_0152099097_ul2099115517587"><li id="dcs-faq-0730026__en-us_topic_0152099097_li399125535811">Redis 3.0<p id="dcs-faq-0730026__en-us_topic_0152099097_p851518115910"><a name="dcs-faq-0730026__en-us_topic_0152099097_li399125535811"></a><a name="en-us_topic_0152099097_li399125535811"></a>Use port 6379 for intra-VPC access.</p>
|
||||
</li><li id="dcs-faq-0730026__en-us_topic_0152099097_li1188105085912">Redis 4.0 and Redis 5.0<p id="dcs-faq-0730026__en-us_topic_0152099097_p12318114516310"><a name="dcs-faq-0730026__en-us_topic_0152099097_li1188105085912"></a><a name="en-us_topic_0152099097_li1188105085912"></a>You can specify a port (ranging from 1 to 65535) or use the default port (6379) for accessing a DCS Redis 4.0 or 5.0 instance. If no port is specified, the default port will be used.</p>
|
||||
</li></ul>
|
||||
<p id="dcs-faq-0730026__p14803202620398">If the instance and the client use different security groups, you must configure access rules for the security groups, allowing access through the specified port. For details, see <a href="en-us_topic_0090662012.html">Security Group Configurations</a>.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730027.html
Normal file
11
docs/dcs/umn/dcs-faq-0730027.html
Normal file
@ -0,0 +1,11 @@
|
||||
<a name="dcs-faq-0730027"></a><a name="dcs-faq-0730027"></a>
|
||||
|
||||
<h1 class="topictitle1">Can I Modify the Connection Addresses for Accessing a DCS Instance?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730027__en-us_topic_0152099097_p1482255016399">After a DCS instance is created, its intra-VPC connection addresses cannot be modified.</p>
|
||||
<p id="dcs-faq-0730027__en-us_topic_0152099097_p1858864302818">For details about accessing DCS instances through clients, see <a href="dcs-ug-0326009.html">Accessing a DCS Redis Instance Through redis-cli</a>.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730029.html
Normal file
11
docs/dcs/umn/dcs-faq-0730029.html
Normal file
@ -0,0 +1,11 @@
|
||||
<a name="dcs-faq-0730029"></a><a name="dcs-faq-0730029"></a>
|
||||
|
||||
<h1 class="topictitle1">Does DCS Support Cross-AZ Deployment?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730029__p15277568910">Master/Standby and cluster DCS Redis instances can be deployed across availability zones (AZs).</p>
|
||||
<ul id="dcs-faq-0730029__en-us_topic_0152099097_ul1253034413517"><li id="dcs-faq-0730029__en-us_topic_0152099097_li35311444514">If instances nodes in an AZ are faulty, nodes in other AZs will not be affected. The standby node automatically becomes the master node to continue to operate, ensuring disaster recovery (DR).</li><li id="dcs-faq-0730029__en-us_topic_0152099097_li7539944115110">Cross-AZ deployment does not compromise the speed of data synchronization between the master and standby nodes.</li></ul>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730030.html
Normal file
11
docs/dcs/umn/dcs-faq-0730030.html
Normal file
@ -0,0 +1,11 @@
|
||||
<a name="dcs-faq-0730030"></a><a name="dcs-faq-0730030"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Does It Take a Long Time to Start a Cluster DCS Instance?</h1>
|
||||
<div id="body1596093268950"><p id="dcs-faq-0730030__en-us_topic_0152099097_p5520132125115">Possible cause: When a cluster instance is started, status and data are synchronized between the nodes of the instance. If a large amount of data is continuously written into the instance before the synchronization is complete, the synchronization will be prolonged and the instance remains in the <strong id="dcs-faq-0730030__b11391941256">Starting</strong> state. After the synchronization is complete, the instance enters the <strong id="dcs-faq-0730030__b68543419518">Running</strong> state.</p>
|
||||
<p id="dcs-faq-0730030__en-us_topic_0152099097_p152755508553">Solution: Start writing data to an instance only after the instance has been started.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
10
docs/dcs/umn/dcs-faq-0730032.html
Normal file
10
docs/dcs/umn/dcs-faq-0730032.html
Normal file
@ -0,0 +1,10 @@
|
||||
<a name="dcs-faq-0730032"></a><a name="dcs-faq-0730032"></a>
|
||||
|
||||
<h1 class="topictitle1">Does DCS for Redis Provide Backend Management Software?</h1>
|
||||
<div id="body1596093268951"><p id="dcs-faq-0730032__en-us_topic_0152099097_p725774243710">No. If you wish to query Redis configurations and usage information, use redis-cli. If you wish to monitor DCS Redis instance metrics, go to the Cloud Eye console. For details on how to configure and view the metrics, see <a href="dcs-ug-0326016.html">Monitoring</a>.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730033.html
Normal file
11
docs/dcs/umn/dcs-faq-0730033.html
Normal file
@ -0,0 +1,11 @@
|
||||
<a name="dcs-faq-0730033"></a><a name="dcs-faq-0730033"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Is Memory of a DCS Redis Instance Used Up by Just a Few Keys?</h1>
|
||||
<div id="body1596093268951"><p id="dcs-faq-0730033__en-us_topic_0152099097_p1559974945710">Possible cause: The output buffer may have occupied an excessive amount of memory.</p>
|
||||
<p id="dcs-faq-0730033__en-us_topic_0152099097_p26117919543">Solution: After connecting to the instance using redis-cli, run the <strong id="dcs-faq-0730033__b964793993117">redis-cli --bigkeys</strong> command to scan for big keys. Then, run the <strong id="dcs-faq-0730033__b16648143913317">info</strong> command to check the output buffer size.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
11
docs/dcs/umn/dcs-faq-0730034.html
Normal file
11
docs/dcs/umn/dcs-faq-0730034.html
Normal file
@ -0,0 +1,11 @@
|
||||
<a name="dcs-faq-0730034"></a><a name="dcs-faq-0730034"></a>
|
||||
|
||||
<h1 class="topictitle1">Can I Recover Data from Deleted DCS Instances?</h1>
|
||||
<div id="body1596093268951"><p id="dcs-faq-0730034__en-us_topic_0152099097_p1631651782618">If a DCS instance is automatically deleted or manually deleted through the Redis client, its data cannot be retrieved. If you have backed up the instance, you can restore its data from the backup. However, the restoration will overwrite the data written in during the period from the backup and the restoration.</p>
|
||||
<p id="dcs-faq-0730034__en-us_topic_0152099097_p16241771816">By default, data is not evicted from DCS instances. You can modify the instance configuration parameters to adjust the eviction policy so that the instance can evict key values.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-0326021.html">Redis Usage</a></div>
|
||||
</div>
|
||||
</div>
|
||||
18
docs/dcs/umn/dcs-faq-0730036.html
Normal file
18
docs/dcs/umn/dcs-faq-0730036.html
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|
||||
<a name="dcs-faq-0730036"></a><a name="dcs-faq-0730036"></a>
|
||||
|
||||
<h1 class="topictitle1">How Do I Clear Redis Data?</h1>
|
||||
<div id="body1596093494759"><p id="dcs-faq-0730036__p1554181735816"><strong id="dcs-faq-0730036__b13826131015254">Exercise caution when clearing data.</strong></p>
|
||||
<ul id="dcs-faq-0730036__ul5345182618333"><li id="dcs-faq-0730036__li1345132623311">Redis 3.0<p id="dcs-faq-0730036__p10964478357"><a name="dcs-faq-0730036__li1345132623311"></a><a name="li1345132623311"></a>Data of a DCS Redis 3.0 instance cannot be cleared on the console, and can only be cleared by the <strong id="dcs-faq-0730036__b689814018266">FLUSHDB</strong> or <strong id="dcs-faq-0730036__b3166163914269">FLUSHALL</strong> command in redis-cli.</p>
|
||||
<p id="dcs-faq-0730036__p8472203333612">Run the <strong id="dcs-faq-0730036__b13145640878138">FLUSHALL</strong> command to clear all the data in the instance.</p>
|
||||
<p id="dcs-faq-0730036__p647293333619">Run the <strong id="dcs-faq-0730036__b12348169898138">FLUSHDB</strong> command to clear the data in the currently selected DB.</p>
|
||||
</li><li id="dcs-faq-0730036__li18813103819364">Redis 4.0 and 5.0<p id="dcs-faq-0730036__p1515135633616"><a name="dcs-faq-0730036__li18813103819364"></a><a name="li18813103819364"></a>To clear data of a DCS Redis 4.0 or 5.0 instance, you can run the <strong id="dcs-faq-0730036__b3485143010548">FLUSHDB</strong> or <strong id="dcs-faq-0730036__b124911430165419">FLUSHALL</strong> command in redis-cli, use the data clearing function on the DCS console, or run the <strong id="dcs-faq-0730036__b1676102514715">FLUSHDB</strong> command on Web CLI.</p>
|
||||
<p id="dcs-faq-0730036__p963916114382">To clear data of a Redis Cluster instance, run the <strong id="dcs-faq-0730036__b9521924153015">FLUSHDB</strong> or <strong id="dcs-faq-0730036__b431212296307">FLUSHALL</strong> command on every shard of the instance. Otherwise, data may not be completely cleared.</p>
|
||||
<div class="note" id="dcs-faq-0730036__note168212515318"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="dcs-faq-0730036__ul191791322143115"><li id="dcs-faq-0730036__li111791022143119">Currently, only DCS Redis 4.0 and 5.0 instances support data clearing by using the DCS console and by running the <strong id="dcs-faq-0730036__b263057135217">FLUSHDB</strong> command on Web CLI.</li><li id="dcs-faq-0730036__li13479118163312">When you run the <strong id="dcs-faq-0730036__b17668192510264">FLUSHDB</strong> command on Web CLI, only one shard is cleared at a time. If there are multiple shards, connect to and run the <strong id="dcs-faq-0730036__b16265133815350">FLUSHDB</strong> command on each master node.</li><li id="dcs-faq-0730036__li1079819242316">Redis Cluster data cannot be cleared by using Web CLI.</li></ul>
|
||||
</div></div>
|
||||
</li></ul>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-190921003.html">Redis Commands</a></div>
|
||||
</div>
|
||||
</div>
|
||||
10
docs/dcs/umn/dcs-faq-0730039.html
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docs/dcs/umn/dcs-faq-0730039.html
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|
||||
<a name="dcs-faq-0730039"></a><a name="dcs-faq-0730039"></a>
|
||||
|
||||
<h1 class="topictitle1">Does DCS for Redis Support the INCR and EXPIRE Commands?</h1>
|
||||
<div id="body1596093494759"><p id="dcs-faq-0730039__en-us_topic_0192035902_p46954821915">Yes. For more information about Redis command compatibility, see <a href="dcs-pd-200312003.html">Command Compatibility</a>.</p>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-190921003.html">Redis Commands</a></div>
|
||||
</div>
|
||||
</div>
|
||||
14
docs/dcs/umn/dcs-faq-0730040.html
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14
docs/dcs/umn/dcs-faq-0730040.html
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|
||||
<a name="dcs-faq-0730040"></a><a name="dcs-faq-0730040"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Do I Fail to Execute Some Redis Commands?</h1>
|
||||
<div id="body1596093494759"><p id="dcs-faq-0730040__en-us_topic_0192035902_p8060118">Possible causes include the following:</p>
|
||||
<ul id="dcs-faq-0730040__en-us_topic_0192035902_ul18525838123819"><li id="dcs-faq-0730040__en-us_topic_0192035902_li6525163893815">The command is incorrect.</li><li id="dcs-faq-0730040__en-us_topic_0192035902_li14525133819383">The command is disabled in DCS.<p id="dcs-faq-0730040__en-us_topic_0192035902_p143284526385"><a name="dcs-faq-0730040__en-us_topic_0192035902_li14525133819383"></a><a name="en-us_topic_0192035902_li14525133819383"></a>For security purposes, some Redis commands are disabled in DCS. For details about disabled and restricted Redis commands, see <a href="dcs-pd-200312003.html">Command Compatibility</a>.</p>
|
||||
</li><li id="dcs-faq-0730040__en-us_topic_0192035902_li15525238183817">The LUA script fails to be executed.<p id="dcs-faq-0730040__en-us_topic_0192035902_p1181171175114"><a name="dcs-faq-0730040__en-us_topic_0192035902_li15525238183817"></a><a name="en-us_topic_0192035902_li15525238183817"></a>For example, the error message "ERR unknown command 'EVAL'" indicates that your DCS Redis instance is of a lower version that does not support the LUA script. In this case, contact technical support for the instance to be upgraded.</p>
|
||||
</li><li id="dcs-faq-0730040__en-us_topic_0192035902_li252573843815">The <strong id="dcs-faq-0730040__b72663418711">CLIENT SETNAME</strong> and <strong id="dcs-faq-0730040__b14311834178">CLIENT GETNAME</strong> commands fail to be executed.<p id="dcs-faq-0730040__en-us_topic_0192035902_p12231923532">This is because the DCS Redis instance is of a lower version that does not support these commands. In this case, contact technical support for the instance to be upgraded.</p>
|
||||
</li></ul>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-190921003.html">Redis Commands</a></div>
|
||||
</div>
|
||||
</div>
|
||||
19
docs/dcs/umn/dcs-faq-0730041.html
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19
docs/dcs/umn/dcs-faq-0730041.html
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@ -0,0 +1,19 @@
|
||||
<a name="dcs-faq-0730041"></a><a name="dcs-faq-0730041"></a>
|
||||
|
||||
<h1 class="topictitle1">Why Does a Redis Command Fail to Take Effect?</h1>
|
||||
<div id="body1596093494759"><p id="dcs-faq-0730041__en-us_topic_0192035902_p1017169153514">Run the command in redis-cli to check whether the command takes effect.</p>
|
||||
<p id="dcs-faq-0730041__en-us_topic_0192035902_p1808164714374">The following describes two scenarios:</p>
|
||||
<ul id="dcs-faq-0730041__en-us_topic_0192035902_ul58061534382"><li id="dcs-faq-0730041__en-us_topic_0192035902_li86421320145219">Scenario 1: Set and query the value of a key to check whether the <strong id="dcs-faq-0730041__b204771411478">SET</strong> and <strong id="dcs-faq-0730041__b24833411373">GET</strong> commands work.<p id="dcs-faq-0730041__en-us_topic_0192035902_p7361226135213">The <strong id="dcs-faq-0730041__b1753111424716">SET</strong> command is used to set the string value. If the value is not changed, run the following commands in redis-cli to access the instance:</p>
|
||||
<p id="dcs-faq-0730041__en-us_topic_0192035902_p6171296354"><span><img id="dcs-faq-0730041__en-us_topic_0192035902_image418199203517" src="en-us_image_0266322522.jpg"></span></p>
|
||||
</li><li id="dcs-faq-0730041__en-us_topic_0192035902_li15497141023813">Scenario 2: If the timeout set using the <strong id="dcs-faq-0730041__b1272412441576">EXPIRE</strong> command is incorrect, perform the following operations:<p id="dcs-faq-0730041__en-us_topic_0192035902_p597831543412">Set the timeout to 10 seconds and run the <strong id="dcs-faq-0730041__b128483452718">TTL</strong> command to view the remaining time. As shown in the following example, the remaining time is 7 seconds.</p>
|
||||
<p id="dcs-faq-0730041__en-us_topic_0192035902_p73301313143416"><span><img id="dcs-faq-0730041__en-us_topic_0192035902_image3330191383413" src="en-us_image_0266322523.png"></span></p>
|
||||
</li></ul>
|
||||
<div class="note" id="dcs-faq-0730041__en-us_topic_0192035902_note56151919396"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="dcs-faq-0730041__en-us_topic_0192035902_p54201911409">Redis clients (including redis-cli, Jedis clients, and Python clients) communicate with Redis server using a binary protocol.</p>
|
||||
<p id="dcs-faq-0730041__en-us_topic_0192035902_p061419203919">If Redis commands are run properly in redis-cli, the problem may lie in the service code. In this case, create logs in the code for further analysis.</p>
|
||||
</div></div>
|
||||
</div>
|
||||
<div>
|
||||
<div class="familylinks">
|
||||
<div class="parentlink"><strong>Parent topic:</strong> <a href="dcs-faq-190921003.html">Redis Commands</a></div>
|
||||
</div>
|
||||
</div>
|
||||
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