This topic introduces the usage notes of ApsaraDB RDS.

After you create an RDS instance, you do not need to conduct basic database operations and maintenance (O&M), such as high availability configuration and security patching. However, you must take note of the following information:

  • Specification change

    When you change the specifications of your RDS instance, an automatic data migration may be triggered. After the migration is complete, ApsaraDB RDS switches your workloads over to a new RDS instance during the switching time that you specify. The switchover does not interrupt the synchronization of incremental data. However, the migration causes network interruptions or transient connection errors. This depends on the edition of your RDS instance. During the network interruptions or transient connection errors, you cannot perform most of the operations that are related to databases, accounts, and network settings.

    Warning
    • If you use the Basic Edition, your RDS instance is not provided with a secondary RDS instance as a hot standby. Therefore, your database service is unavailable during a specification change. The length of time during which your database service is unavailable may be 30 minutes or more. We recommend that you change the specifications of your RDS instance during off-peak hours. This prevents interruptions to your workloads.
    • If you do not use the Basic Edition, a specification change may cause transient connection errors that last about 30 seconds. This does not interrupt your workloads. However, we still recommend that you change the specifications of your RDS during off-peak hours. Otherwise, make sure that your application is configured to automatically reconnect to your RDS instance.
    Note In most cases, if your RDS instance uses standard or enhanced SSDs and does not run the RDS Basic Edition, no transient connection errors occur when you increase the storage capacity.
  • Version upgrade
    When you upgrade the minor or major engine version of your RDS instance, you experience network interruptions or transient connection errors. This depends on the edition of your RDS instance. For example, if you upgrade the major engine version from MySQL 5.5 to MySQL 5.6, you experience network interruption or transient connection errors. During the network interruptions or transient connection errors, you cannot perform most of the operations that are related to databases, accounts, and network settings.
    Warning
    • If you use the Basic Edition, your RDS instance is not provided with a secondary RDS instance as a hot standby. Therefore, your database service is unavailable during a database engine version upgrade. The length of time during which your database service is unavailable may be 30 minutes or more. We recommend that you upgrade the database engine version of your RDS instance during off-peak hours. This prevents interruptions to your workloads.
    • If you do not use the Basic Edition, a database engine version upgrade may cause transient connection errors that last about 30 seconds. This does not interrupt your workloads. However, we still recommend that you upgrade the database engine version of your RDS during off-peak hours. Otherwise, make sure that your application is configured to automatically reconnect to your RDS instance.
  • Failover

    In the High-availability or Enterprise Edition, your database system consists of a primary RDS instance and a secondary RDS instance. If the primary RDS instance unexpectedly exits, your database system fails over to the secondary RDS instance within 30 seconds. During the failover, you experience transient connection errors that last about 30 seconds. We recommend that you configure your application to automatically reconnect to your database system. This allows you to prevent interruptions to your workloads.

  • Network change

    When you switch your RDS instance between the classic network and a virtual private cloud (VPC), the server on which your application runs is disconnected from your RDS instance. In addition, the IP addresses of your RDS instance change. After the switchover is complete, we recommend that you immediately update the endpoint configuration on your application.

  • Data restoration

    We recommend that you back up the important data of your RDS instance on a regular basis. This prevents data losses. We also recommend that you restore data by using a temporary or cloned RDS instance. In this case, you must first create a temporary or cloned RDS instance. Then, you can restore the data of your original RDS instance to the temporary or cloned RDS instance. After you verify the data on the temporary or cloned RDS instance, you can migrate the data back to your original RDS instance.

  • Storage capacity

    If the storage capacity of your RDS instance is exhausted, ApsaraDB RDS locks the instance. In this case, you can only read data from the instance. We recommend that you check the storage usage of your RDS instance on a regular basis.

  • Performance optimization
    • You must check whether the number of CPU cores, memory capacity, input/output operations per second (IOPS), storage capacity, and maximum number of connections for your RDS instance are sufficient. Then, you can optimize or upgrade your RDS instance if required.
    • You must check whether your RDS instance runs as normal. For example, you can check whether a large number of SQL statements are executed at low speeds, whether SQL statements need to be optimized, and whether some indexes are unnecessary or missing. Then, you can resolve all the identified issues.