This topic describes the limits and usage notes of ApsaraDB RDS.
After you create an RDS instance, you do not need to perform basic database O&M operations, such as high availability configuration and security patching. However, you must take note of the items that are described in the following table.
|Specification change||When you change the specifications of your RDS instance, ApsaraDB RDS may migrate
the data of your RDS instance to a new RDS instance. The incremental data that is
generated in your RDS instance during the migration process continues to be synchronized
to the new RDS instance. After the migration process is complete, ApsaraDB RDS switches
your workloads over to the new RDS instance during the switching time that you specify.
During the migration process, network interruptions or transient connections may occur.
The actual situation varies based on the RDS edition that is used. If network interruptions
or transient connections occur, you cannot perform most of the operations that are
related to databases, accounts, and network settings.
|Version upgrade||When you upgrade the major engine version or update the minor engine version of your
RDS instance, network interruptions or transient connections may occur. The actual
situation varies based on the RDS edition that is used. If network interruptions or
transient connections occur, you cannot perform most of the operations that are related
to databases, accounts, and network settings.
|Failover||In the RDS High-availability Edition or the RDS Enterprise Edition, your RDS instance is provided with a secondary RDS instance as a hot standby. If your RDS instance unexpectedly exits, your database services can fail over to the secondary RDS instance within 30 seconds. During the failover process, a transient connection that lasts about 30 seconds occur. 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 migrate 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 migration process is complete, we recommend that you immediately update the endpoint configuration on your application.|
|Data restoration||Before you restore the data of your RDS instance, we recommend that you back up the important data on your RDS instance to prevent data loss. We also recommend that you restore the data of your RDS instance by using a temporary RDS instance or a cloned RDS instance. You must first create a temporary RDS instance or a cloned RDS instance. Then, you can restore the data of your original RDS instance to the temporary RDS instance or the cloned RDS instance. After you verify the data on the temporary RDS instance or the 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 on a regular basis.
Note If the storage usage is abnormally high, see What do I do if my ApsaraDB RDS for MySQL instance is locked because its storage capacity is exhausted?