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<h1 class="topictitle1">Backing Up HDFS Service Data</h1>
<div id="body1530063339476"><div class="section" id="admin_guide_000209__s62b8da2d7ece40c69a0d0898bb3ff888"><h4 class="sectiontitle">Scenario</h4><p id="admin_guide_000209__en-us_topic_0046736766_p8137613">To ensure HDFS service data security routinely or before a major operation on HDFS (such as upgrade or migration), you need to back up HDFS service data. The backup data can be used to recover the system if an exception occurs or the operation has not achieved the expected result, minimizing the adverse impacts on services.</p>
<p id="admin_guide_000209__en-us_topic_0046736766_p6129654">You can create a backup task on <span id="admin_guide_000209__text67509419010">MRS</span> Manager to back up HDFS service data. Both automatic and manual backup tasks are supported.</p>
<div class="note" id="admin_guide_000209__note11668124185620"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="admin_guide_000209__p18686204175613">Encrypted directories cannot be backed up or restored.</p>
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<div class="section" id="admin_guide_000209__s7facb65a87d642f7aa66a403faafaa3d"><h4 class="sectiontitle">Prerequisites</h4><ul id="admin_guide_000209__ul114846295169"><li id="admin_guide_000209__lf3c3f51380734b469b9ab66e4015777c">If data needs to be backed up to the remote HDFS, you have prepared a standby cluster for data backup. The authentication mode of the standby cluster is the same as that of the active cluster. For other backup modes, you do not need to prepare the standby cluster.</li><li id="admin_guide_000209__l6b2ccbf0a54a4d7994c8b888340d4fc3">If the active cluster is deployed in security mode and the active and standby clusters are not managed by the same <span id="admin_guide_000209__text19327632141510">MRS</span> Manager, mutual trust has been configured. For details, see <a href="admin_guide_000177.html">Configuring Cross-Manager Mutual Trust Between Clusters</a>. If the active cluster is deployed in normal mode, no mutual trust is required.</li><li id="admin_guide_000209__lfde42b9aa55947f79d6253ef3ddd298b">Cross-cluster replication has been configured for the active and standby clusters. For details, see <a href="admin_guide_000200.html">Enabling Cross-Cluster Replication</a>.</li></ul>
<ul id="admin_guide_000209__ul10245183811161"><li id="admin_guide_000209__lb80a243195ff415bb79d73f765e4982c">Time is consistent between the active and standby clusters and the NTP services on the active and standby clusters use the same time source.</li></ul>
<ul id="admin_guide_000209__en-us_topic_0046736766_ul26740005"><li id="admin_guide_000209__en-us_topic_0046736766_li9361906">Backup policies, including the backup task type, period, backup object, backup directory, and Yarn queue required by the backup task are planned based on service requirements.</li><li id="admin_guide_000209__en-us_topic_0046736766_li17148294">The HDFS in the standby cluster has sufficient space. You are advised to save backup files in a custom directory.</li><li id="admin_guide_000209__en-us_topic_0046736766_li20116922">On the HDFS client, you have executed the <strong id="admin_guide_000209__b155541935182619">hdfs lsSnapshottableDir</strong> command as user <strong id="admin_guide_000209__b15561123516268">hdfs</strong> to check the list of directories for which HDFS snapshots have been created in the current cluster and ensured that the HDFS parent directory or subdirectory where data files to be backed up are stored does not have HDFS snapshots. Otherwise, the backup task cannot be created.</li><li id="admin_guide_000209__li9837811115617">If you want to back up data to NAS, you have deployed the NAS server in advance.</li></ul>
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<div class="section" id="admin_guide_000209__sc1d32a5bd1f34de893dc813b8e9b0b89"><h4 class="sectiontitle">Procedure</h4><ol id="admin_guide_000209__ol56207616154730"><li id="admin_guide_000209__li514247915256"><span>On <span id="admin_guide_000209__text1185616356152">MRS</span> Manager, choose <strong id="admin_guide_000209__b416195419272">O&amp;M</strong> &gt; <strong id="admin_guide_000209__b2163125432713">Backup and Restoration</strong> &gt; <strong id="admin_guide_000209__b9164145422711">Backup Management</strong>.</span></li><li id="admin_guide_000209__li1388766715256"><span>Click <strong id="admin_guide_000209__b1848263673112918">Create</strong>.</span></li><li id="admin_guide_000209__li5788013915256"><span>Set <strong id="admin_guide_000209__b18436357142716">Name</strong> to the name of the backup task.</span></li><li id="admin_guide_000209__li2832102653918"><span>Select the cluster to be operated from <strong id="admin_guide_000209__b1143115911274">Backup Object</strong>.</span></li><li id="admin_guide_000209__li1759563715256"><span>Set <strong id="admin_guide_000209__b8208111172811">Mode</strong> to the type of the backup task.</span><p><p id="admin_guide_000209__en-us_topic_0165590410_p226614614816"><strong id="admin_guide_000209__b1110416319281">Periodic</strong> indicates that the backup task is executed by the system periodically. <strong id="admin_guide_000209__b1010511372815">Manual</strong> indicates that the backup task is executed manually.</p>

<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" id="admin_guide_000209__en-us_topic_0165590410_table193081738154917" frame="border" border="1" rules="all"><caption><b>Table 1 </b>Periodic backup parameters</caption><thead align="left"><tr id="admin_guide_000209__en-us_topic_0165590410_row430813818490"><th align="left" class="cellrowborder" valign="top" width="21.84%" id="mcps1.3.3.2.5.2.2.2.3.1.1"><p id="admin_guide_000209__en-us_topic_0165590410_p113081938184918">Parameter</p>
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<th align="left" class="cellrowborder" valign="top" width="78.16%" id="mcps1.3.3.2.5.2.2.2.3.1.2"><p id="admin_guide_000209__en-us_topic_0165590410_p173081538114915">Description</p>
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<tbody><tr id="admin_guide_000209__en-us_topic_0165590410_row18308838144917"><td class="cellrowborder" valign="top" width="21.84%" headers="mcps1.3.3.2.5.2.2.2.3.1.1 "><p id="admin_guide_000209__en-us_topic_0165590410_p030893804920">Started</p>
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<td class="cellrowborder" valign="top" width="78.16%" headers="mcps1.3.3.2.5.2.2.2.3.1.2 "><p id="admin_guide_000209__en-us_topic_0165590410_p103081838144917">Indicates the time when the task is started for the first time.</p>
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<tr id="admin_guide_000209__en-us_topic_0165590410_row1530813813494"><td class="cellrowborder" valign="top" width="21.84%" headers="mcps1.3.3.2.5.2.2.2.3.1.1 "><p id="admin_guide_000209__en-us_topic_0165590410_p1930833815494">Period</p>
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<td class="cellrowborder" valign="top" width="78.16%" headers="mcps1.3.3.2.5.2.2.2.3.1.2 "><p id="admin_guide_000209__en-us_topic_0165590410_p7308183834918">Indicates the task execution interval. The options include <strong id="admin_guide_000209__b1533781215285">Hours</strong> and <strong id="admin_guide_000209__b733914120286">Days</strong>.</p>
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<tr id="admin_guide_000209__en-us_topic_0165590410_row7308103810493"><td class="cellrowborder" valign="top" width="21.84%" headers="mcps1.3.3.2.5.2.2.2.3.1.1 "><p id="admin_guide_000209__en-us_topic_0165590410_p16308153834910">Backup Policy</p>
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<td class="cellrowborder" valign="top" width="78.16%" headers="mcps1.3.3.2.5.2.2.2.3.1.2 "><ul id="admin_guide_000209__en-us_topic_0165590410_ul17277134745017"><li id="admin_guide_000209__en-us_topic_0165590410_li7277247105018"><strong id="admin_guide_000209__b363261147112918">Full backup at the first time and incremental backup subsequently</strong></li><li id="admin_guide_000209__en-us_topic_0165590410_li0512161105112"><strong id="admin_guide_000209__b1136810350112918">Full backup every time</strong></li><li id="admin_guide_000209__en-us_topic_0165590410_li10673122011516"><strong id="admin_guide_000209__b1850653638112918">Full backup once every n times</strong></li></ul>
<div class="note" id="admin_guide_000209__en-us_topic_0165590410_note181551254522"><span class="notetitle"> NOTE: </span><div class="notebody"><ul id="admin_guide_000209__en-us_topic_0165590410_ul61731492817"><li id="admin_guide_000209__en-us_topic_0165590410_li161733452817">Incremental backup is not supported when Manager data and component metadata are backed up. Only <strong id="admin_guide_000209__b72181551133012">Full backup every time</strong> is supported.</li><li id="admin_guide_000209__en-us_topic_0165590410_li1074775142813">If <strong id="admin_guide_000209__b1330311546304">Path Type</strong> is set to <strong id="admin_guide_000209__b113051354153017">NFS</strong> or <strong id="admin_guide_000209__b7306135433018">CIFS</strong>, incremental backup cannot be used. When incremental backup is used for NFS or CIFS backup, the latest full backup data is updated each time the incremental backup is performed. Therefore, no new recovery point is generated.</li></ul>
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</p></li><li id="admin_guide_000209__li22282512154730"><span>In <strong id="admin_guide_000209__b1939516019312">Configuration</strong>, select <strong id="admin_guide_000209__b163969053110">HDFS</strong>.</span></li><li id="admin_guide_000209__li4457996415256"><span>Set <strong id="admin_guide_000209__b4740187123119">Path Type</strong> of <strong id="admin_guide_000209__b274119713316">HDFS</strong> to a backup directory type.</span><p><p class="litext" id="admin_guide_000209__p1596050715256">The following backup directory types are supported:</p>
<ul class="subitemlist" id="admin_guide_000209__u695c04bfc9fd4e808744a464ebe243f6"><li class="subitemlist" id="admin_guide_000209__li24631029435"><strong id="admin_guide_000209__b695061653111">RemoteHDFS</strong>: indicates that the backup files are stored in the HDFS directory of the standby cluster.<div class="subitemlist" id="admin_guide_000209__p17481627437">If you select this option, set the following parameters:<ul id="admin_guide_000209__ul165141635941"><li id="admin_guide_000209__li10541031232"><strong id="admin_guide_000209__b623752193112">Destination NameService Name</strong>: indicates the NameService name of the standby cluster. You can set it to the NameService name (<strong id="admin_guide_000209__b1760322510319">haclusterX</strong>, <strong id="admin_guide_000209__b156054258316">haclusterX1</strong>, <strong id="admin_guide_000209__b15606425123113">haclusterX2</strong>, <strong id="admin_guide_000209__b8608325193115">haclusterX3</strong>, or <strong id="admin_guide_000209__b1860942510319">haclusterX4</strong>) of the built-in remote cluster of the cluster, or the NameService name of a configured remote cluster.</li></ul>
<ul id="admin_guide_000209__ucd7932b194e14ccaacbee7182305411e"><li id="admin_guide_000209__li1330023122312"><strong id="admin_guide_000209__b141261628123118">IP Mode</strong>: indicates the mode of the target IP address. The system automatically selects the IP address mode based on the cluster network type, for example, <strong id="admin_guide_000209__b48361530173116">IPv4</strong> or <strong id="admin_guide_000209__b18371230133116">IPv6</strong>.</li><li id="admin_guide_000209__l7490b5c195bd4078bd573fe51446a0c8"><strong id="admin_guide_000209__b2536203973120">Target NameNode IP Address</strong>: indicates the IP address of the NameNode service plane in the standby cluster. It can be of an active or standby node.</li><li id="admin_guide_000209__l5925782c9fc64eb7a451cb59d1cd0ce6"><strong id="admin_guide_000209__b1515911426311">Target Path</strong>: indicates the HDFS directory for storing standby cluster backup data. The storage path cannot be an HDFS hidden directory, such as a snapshot or recycle bin directory, or a default system directory, such as <strong id="admin_guide_000209__b1149144143112">/hbase</strong> or <strong id="admin_guide_000209__b191502443312">/user/hbase/backup</strong>.</li><li id="admin_guide_000209__l08a160fa37f8497787268df5a45d620c"><strong id="admin_guide_000209__b01272047173114">Maximum Number of Backup Copies</strong>: indicates the number of backup file sets that can be retained in the backup directory.</li><li id="admin_guide_000209__l4f27e9a8307c43fab688eb38ffd050d8"><strong id="admin_guide_000209__b19668204911318">Queue Name</strong>: indicates the name of the Yarn queue used for backup task execution. The name must be the same as the name of the queue that is running properly in the cluster.</li><li id="admin_guide_000209__li558713234547"><strong id="admin_guide_000209__b17401553143116">Maximum Number of Maps</strong>: indicates the maximum number of maps in a MapReduce task. The default value is <strong id="admin_guide_000209__b1441165393119">20</strong>.</li><li id="admin_guide_000209__li1458818232549"><strong id="admin_guide_000209__b163449551313">Maximum Bandwidth of a Map (MB/s)</strong>: indicates the maximum bandwidth of a map. The default value is <strong id="admin_guide_000209__b834535563119">100</strong>.</li><li id="admin_guide_000209__li590823415454"><strong id="admin_guide_000209__b34846373213">NameService Name</strong>: indicates the NameService name of the backup directory. The default value is <strong id="admin_guide_000209__b108441512327">hacluster</strong>.</li></ul>
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</li><li class="subitemlist" id="admin_guide_000209__li1682310513434"><strong id="admin_guide_000209__b755267193212">NFS</strong>: indicates that backup files are stored in the NAS using the NFS protocol.<div class="subitemlist" id="admin_guide_000209__p255146144310">If you select this option, set the following parameters:<ul id="admin_guide_000209__ul127408275"><li id="admin_guide_000209__li040871275519"><strong id="admin_guide_000209__b106941911163218">IP Mode</strong>: indicates the mode of the target IP address. The system automatically selects the IP address mode based on the cluster network type, for example, <strong id="admin_guide_000209__b6415201323214">IPv4</strong> or <strong id="admin_guide_000209__b64161313143218">IPv6</strong>.</li></ul>
<ul id="admin_guide_000209__ul131981043121213"><li id="admin_guide_000209__li84531639101211"><strong id="admin_guide_000209__b615861553213">Server IP Address</strong>: indicates the IP address of the NAS server.</li><li id="admin_guide_000209__li87592021162817"><strong id="admin_guide_000209__b11100117153214">Maximum Number of Backup Copies</strong>: indicates the number of backup file sets that can be retained in the backup directory.</li><li id="admin_guide_000209__li1823404503"><strong id="admin_guide_000209__b10360171915327">Server Shared Path</strong>: indicates the configured shared directory of the NAS server. (The shared path of the server cannot be set to the root directory, and the user group and owner group of the shared path must be <strong id="admin_guide_000209__b121081526153612">nobody:nobody</strong>.)</li><li id="admin_guide_000209__li39791015185012"><strong id="admin_guide_000209__b6124221103215">Queue Name</strong>: indicates the name of the Yarn queue used for backup task execution. The name must be the same as the name of the queue that is running properly in the cluster.</li><li id="admin_guide_000209__li67021518182217"><strong id="admin_guide_000209__b1036217241327">Maximum Number of Maps</strong>: indicates the maximum number of maps in a MapReduce task. The default value is <strong id="admin_guide_000209__b0363152411321">20</strong>.</li><li id="admin_guide_000209__li207044187226"><strong id="admin_guide_000209__b5515152614322">Maximum Bandwidth of a Map (MB/s)</strong>: indicates the maximum bandwidth of a map. The default value is <strong id="admin_guide_000209__b14516122613322">100</strong>.</li><li id="admin_guide_000209__li15213656154718"><strong id="admin_guide_000209__b1151733093217">NameService Name</strong>: indicates the NameService name of the backup directory. The default value is <strong id="admin_guide_000209__b282783233214">hacluster</strong>.</li></ul>
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</li><li id="admin_guide_000209__li153151517158"><strong id="admin_guide_000209__b186441034143212">CIFS</strong>: indicates that backup files are stored in the NAS using the CIFS protocol. If you select this option, set the following parameters:<ul id="admin_guide_000209__ul19998175216165"><li id="admin_guide_000209__li730849102815"><strong id="admin_guide_000209__b11129193918320">IP Mode</strong>: indicates the mode of the target IP address. The system automatically selects the IP address mode based on the cluster network type, for example, <strong id="admin_guide_000209__b2184194113215">IPv4</strong> or <strong id="admin_guide_000209__b121859416324">IPv6</strong>.</li><li id="admin_guide_000209__li14202144861616"><strong id="admin_guide_000209__b2088115422321">Server IP Address</strong>: indicates the IP address of the NAS server.</li><li id="admin_guide_000209__li5203184891618"><strong id="admin_guide_000209__b561914448328">Port</strong>: indicates the port number used to connect to the NAS server over the CIFS protocol. The default value is <strong id="admin_guide_000209__b13621154453210">445</strong>.</li><li id="admin_guide_000209__li121901359121615"><strong id="admin_guide_000209__b11527184612357">Username</strong>: indicates the username set when the CIFS protocol is configured.</li><li id="admin_guide_000209__li10297967178"><strong id="admin_guide_000209__b12531648113512">Password</strong>: indicates the password set when the CIFS protocol is configured.</li><li id="admin_guide_000209__li1393393195018"><strong id="admin_guide_000209__b16318195014353">Maximum Number of Backup Copies</strong>: indicates the number of backup file sets that can be retained in the backup directory.</li><li id="admin_guide_000209__li1220411480164"><strong id="admin_guide_000209__b542365273516">Server Shared Path</strong>: indicates the configured shared directory of the NAS server. (The shared path of the server cannot be set to the root directory, and the user group and owner group of the shared path must be <strong id="admin_guide_000209__b199111027153620">nobody:nobody</strong>.)</li><li id="admin_guide_000209__li991684118507"><strong id="admin_guide_000209__b1966755517357">Queue Name</strong>: indicates the name of the Yarn queue used for backup task execution. The name must be the same as the name of the queue that is running properly in the cluster.</li><li id="admin_guide_000209__li175164215235"><strong id="admin_guide_000209__b1816612083617">Maximum Number of Maps</strong>: indicates the maximum number of maps in a MapReduce task. The default value is <strong id="admin_guide_000209__b2168200193618">20</strong>.</li><li id="admin_guide_000209__li175418420238"><strong id="admin_guide_000209__b1213819311369">Maximum Bandwidth of a Map (MB/s)</strong>: indicates the maximum bandwidth of a map. The default value is <strong id="admin_guide_000209__b1413915373613">100</strong>.</li><li id="admin_guide_000209__li894111306483"><strong id="admin_guide_000209__b12939366367">NameService Name</strong>: indicates the NameService name of the backup directory. The default value is <strong id="admin_guide_000209__b16173294363">hacluster</strong>.</li></ul>
</li><li class="subitemlist" id="admin_guide_000209__li441312313569"><strong id="admin_guide_000209__b1011131117363">SFTP</strong>: indicates that backup files are stored in the server using the SFTP protocol.<div class="subitemlist" id="admin_guide_000209__p841418318563">If you select this option, set the following parameters:<ul id="admin_guide_000209__ul11200135402812"><li id="admin_guide_000209__li820045416286"><strong id="admin_guide_000209__b157114158364">IP Mode</strong>: indicates the mode of the target IP address. The system automatically selects the IP address mode based on the cluster network type, for example, <strong id="admin_guide_000209__b3286161711364">IPv4</strong> or <strong id="admin_guide_000209__b1728818175369">IPv6</strong>.</li></ul>
<ul id="admin_guide_000209__ul241493118561"><li id="admin_guide_000209__li97815717100"><strong id="admin_guide_000209__b133415195362">Server IP Address</strong>: indicates the IP address of the server where the backup data is stored.</li><li id="admin_guide_000209__li479145741011"><strong id="admin_guide_000209__b438382143616">Port</strong>: indicates the port number used to connect to the backup server over the SFTP protocol. The default value is <strong id="admin_guide_000209__b538432114369">22</strong>.</li><li id="admin_guide_000209__li879757121015"><strong id="admin_guide_000209__b20300523203612">Username</strong>: indicates the username for connecting to the server using the SFTP protocol.</li><li id="admin_guide_000209__li177955791018"><strong id="admin_guide_000209__b1631625163612">Password</strong>: indicates the password for connecting to the server using the SFTP protocol.</li><li id="admin_guide_000209__li9795574105"><strong id="admin_guide_000209__b14259142723620">Server Shared Path</strong>: indicates the backup path on the SFTP server.</li><li id="admin_guide_000209__li11414113111563"><strong id="admin_guide_000209__b112421029113620">Maximum Number of Backup Copies</strong>: indicates the number of backup file sets that can be retained in the backup directory.</li><li id="admin_guide_000209__li167057113403"><strong id="admin_guide_000209__b1045013233611">Queue Name</strong>: indicates the name of the Yarn queue used for backup task execution. The name must be the same as the name of the queue that is running properly in the cluster.</li><li id="admin_guide_000209__li157051315403"><strong id="admin_guide_000209__b69821336123615">Maximum Number of Maps</strong>: indicates the maximum number of maps in a MapReduce task. The default value is <strong id="admin_guide_000209__b12983193623617">20</strong>.</li><li id="admin_guide_000209__li570518120407"><strong id="admin_guide_000209__b491317392368">Maximum Bandwidth of a Map (MB/s)</strong>: indicates the maximum bandwidth of a map. The default value is <strong id="admin_guide_000209__b19144391365">100</strong>.</li><li id="admin_guide_000209__li157053114012"><strong id="admin_guide_000209__b0576194393610">NameService Name</strong>: indicates the NameService name of the backup directory. The default value is <strong id="admin_guide_000209__b02051746203620">hacluster</strong>.</li></ul>
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</li></ul>
</p></li><li id="admin_guide_000209__li57375838154730"><span>Set <strong id="admin_guide_000209__b104622483361">Maximum Number of Recovery Points</strong> to the number of snapshots that can be retained in the cluster.</span></li><li id="admin_guide_000209__li20998871154730"><span>Set <strong id="admin_guide_000209__b123631148173711">Backup Content</strong> to one or multiple HDFS directories to be backed up based on service requirements.</span><p><p id="admin_guide_000209__p46620496154730">You can select backup data using either of the following methods:</p>
<ul id="admin_guide_000209__ul61985531154730"><li id="admin_guide_000209__li50756172154428">Adding a backup data file<p id="admin_guide_000209__en-us_topic_0000001196982039_p1322548161715"><a name="admin_guide_000209__li50756172154428"></a><a name="li50756172154428"></a>Click the name of a database in the navigation tree to show all the tables in the database, and select specified tables.</p>
</li><li id="admin_guide_000209__li29256902154730">Selecting using regular expressions<ol type="a" id="admin_guide_000209__ol56590999154810"><li id="admin_guide_000209__li47181076154810">Click <strong id="admin_guide_000209__b928466076112918">Query Regular Expression</strong>.</li><li id="admin_guide_000209__li21976500154810">Enter the parent directory full path of the directory in the first text box as prompted. The directory must be the same as the existing directory, for example, <strong id="admin_guide_000209__b1819720059112918">/tmp</strong>.</li><li id="admin_guide_000209__li48959393154810">Enter a regular expression in the second text box. Standard regular expressions are supported. For example, to get all files or subdirectories in the parent directory, enter <strong id="admin_guide_000209__b623490874112918">([\s\S]*?)</strong>. To get files whose names consist of letters and digits, for example, <strong id="admin_guide_000209__b35266094154810">file<em id="admin_guide_000209__i63570778154810">1</em></strong>, enter <strong id="admin_guide_000209__b13141163253918">file\d*</strong>.</li><li id="admin_guide_000209__li37981356154810">Click <strong id="admin_guide_000209__b1766161816402">Refresh</strong> to view the displayed directories in <strong id="admin_guide_000209__b206691518184011">Directory Name</strong>.</li><li id="admin_guide_000209__li6287888154810">Click <strong id="admin_guide_000209__b891743985112918">Synchronize</strong> to save the result.</li></ol>
<div class="note" id="admin_guide_000209__en-us_topic_0046736766_note61044600"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><ul id="admin_guide_000209__en-us_topic_0046736766_ul12530496"><li id="admin_guide_000209__en-us_topic_0046736766_li45665605">When entering regular expressions, click <span><img id="admin_guide_000209__image2025292243311" src="en-us_image_0000001442494045.png"></span> or <span><img id="admin_guide_000209__image134691822163514" src="en-us_image_0000001442413869.png"></span> to add or delete an expression.</li><li id="admin_guide_000209__en-us_topic_0046736766_li4229764">If the selected table or directory is incorrect, click <strong id="admin_guide_000209__b2753756144019">Clear Selected Node</strong> to deselect it.</li><li id="admin_guide_000209__li156286566346">The backup directory cannot contain files that have been written for a long time. Otherwise, the backup task will fail. Therefore, you are not advised to perform operations on the top-level directory, such as <strong id="admin_guide_000209__b1780546174112918">/user</strong>, <strong id="admin_guide_000209__b864611336112918">/tmp</strong>, and <strong id="admin_guide_000209__b1386763069112918">/mr-history</strong>.</li></ul>
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</p></li><li id="admin_guide_000209__en-us_topic_0046736766_li7066597"><span>Click <strong id="admin_guide_000209__b10480122774116">Verify</strong> to check whether the backup task is configured correctly.</span><p><p class="litext" id="admin_guide_000209__en-us_topic_0046736766_p63599373">The possible causes of the verification failure are as follows:</p>
<ul class="subitemlist" id="admin_guide_000209__en-us_topic_0046736766_ul35523450"><li id="admin_guide_000209__en-us_topic_0046736766_li51275595">The target NameNode IP address is incorrect.</li><li id="admin_guide_000209__en-us_topic_0046736766_li58827179">The queue name is incorrect.</li><li id="admin_guide_000209__en-us_topic_0046736766_li59682570">The parent directory or subdirectory of the HDFS directory where data files to be backed up are stored has HDFS snapshots.</li><li id="admin_guide_000209__en-us_topic_0046736766_li272226">The directory or table to be backed up does not exist.</li><li id="admin_guide_000209__en-us_topic_0046736766_li2450034">The name of the NameService is incorrect.</li></ul>
</p></li><li id="admin_guide_000209__en-us_topic_0046736766_li22050308"><span>Click <strong id="admin_guide_000209__b1786014560112918">OK</strong>.</span></li><li id="admin_guide_000209__en-us_topic_0046736766_li41244539"><span>In the <strong id="admin_guide_000209__b16281245134214">Operation</strong> column of the created task in the backup task list, click <strong id="admin_guide_000209__b16636445144212">More</strong> and select <strong id="admin_guide_000209__b1363764504216">Back Up Now</strong> to execute the backup task.</span><p><p id="admin_guide_000209__en-us_topic_0046736766_p52473391">After the backup task is executed, the system automatically creates a subdirectory for each backup task in the backup directory. The format of the subdirectory name is <em id="admin_guide_000209__i18237155214427">Backup task name_Data source_Task creation time</em>, and the subdirectory is used to save latest data source backup files. All the backup file sets are stored in the related snapshot directories.</p>
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<div class="parentlink"><strong>Parent topic:</strong> <a href="admin_guide_000201.html">Backing Up Data</a></div>
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