RDS regularly backs up database data to guarantee data integrity, reliability, and restorability.
RDS provides the following two backup functions:
Data backup: This function cannot be disabled. Full physical data backup is performed in a specified period on two or more days every week. In addition, you can manually initiate a full physical data backup on the console or using an API anytime.
Log backup: You can choose to enable or disable this function. If log backup is disabled, you can restore data only to the time when a data backup set is created.
For either data or log backups, you can set the backup retention period to a value ranging from 7 to 730 days. You can set a small value to delete old backups in real time.
Data recoverability is a key indicator of database reliability.
RDS provides the following three recovery functions:
Recover by backup set ID: Recover the data of a backup set to a temporary or clone instance and check data integrity on the temporary or clone instance.
Recover by time: Select a point in time so that the system recovers the full backup and subsequent log backups to a temporary or clone instance. This method is available only if log backup is enabled.
Overwrite and recover: Recover the data of a backup set to the current RDS instance instead of a temporary or clone instance. Exercise caution because this method overwrites data on the current instance.
The recovery functions are closely related to the backup functions:
The early time for data recovery depends on the previous data backup, which is related to the data backup frequency and the data expiration policy.
The late time for data recovery depends on the next log backup, which is closely related to the log volume.
The speed of data recovery depends on the data backup frequency and is also closely related to the log volume.