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    • C

      config is a special mongod that stores metadata of a DB instance. config is deployed as a replica set. To create a DB instance or modify metadata of a DB instance, config must be available.

    • D
      database master password

      A string that defines the password for the database master user. The database master password is a string of 8 to 32 characters. It must contain uppercase letters, lowercase letters, digits, and special characters. You can use the following special characters: ~!@#%^*-_=+?

      database user

      A user that accesses DDS. Currently, the default username is rwuser.

      DB parameter group

      A database parameter group functions as a container for engine configuration values that can be applied to one or more DB instances. If users create a DB instance without specifying a DB parameter group, the default parameter group is used. The default parameter group contains the default values of the engine and database system optimized for the running DB instances. If users want their DB instances to run with their self-defined engine configuration values, they can simply create a new database parameter group, modify certain parameters, and associate the new DB parameter group to a DB instance. Once associated, all DB instances that use this particular DB parameter group get all the parameter updates to that DB parameter group.


      See Document Database Service

      Document Database Service

      DDS is a database service compatible with the MongoDB protocol and is secure, highly available, reliable, scalable, and easy to use. It provides DB instance creation, scaling, redundancy, backup, restoration, monitoring, and alarm reporting functions with just a few clicks on the DDS console.


      • K-O

        A major process in DDS. mongod mainly processes data requests and manages data access.


        A router for data read and write, providing a unified interface for accessing DB instances.


        • R
          replica set

          A replica set consists of a set of mongod processes and provides a collection of data nodes to ensure data redundancy and high availability (HA).

        • S

          Each shard is a mongod process that stores a subset of data for a DB instance. All shards store all data for a DB instance. Generally, each shard is deployed as a replica set to ensure data redundancy and HA.