DDS uses multiple mongos, replica sets, and shards to ensure data reliability. When a mongos is faulty, the other mongos takes over services immediately to ensure service continuity. A replica set consists of a primary, a secondary, and a hidden node. When the primary node is faulty, DDS selects the secondary node as the new primary within 30 seconds.
After purchasing DDS DB instances, you do not need to perform basic database O&M operations, such as HA and security patches. You need to pay attention to the following: