Automatically clear backup data

You can automatically clear backup data as needed.

Notes

• Only data stored in the backup destination specified by backup_dest can be automatically cleared. If the destination of a backup has been changed, it must be manually cleared upon expiration.

• Automatic data clearing will retain at least one valid backup copy. If an expired backup is the only valid copy, it will not be automatically cleared.

Enable automatic data clearing by using the backup_dest_option configuration item

1. Log on to the database as the root user of the sys tenant.

2. Run the following command to set the expiration time and clearing policy of backup data by using the backup_dest_option configuration item.

   The following example enables automatic clearing of data older than seven days.

   obclient> ALTER SYSTEM SET backup_dest_option='log_archive_checkpoint_interval=2m&recovery_window=7d&auto_delete_obsolete_backup=true&log_archive_piece_switch_interval=120s&backup_copies=2';
   

   In the command:

   • log_archive_checkpoint_interval specifies the interval for log backup.

     If you do not specify this parameter in the backup_dest_option configuration item, the value of the cluster-level configuration item log_archive_checkpoint_interval is used by default. If you do not specify either backup_dest_option or log_archive_checkpoint_interval, the default value 120s is used. We recommend that you use backup_dest_option to specify the interval for log backup.

   • recovery_window specifies the retention period of backup data.

     If you do not specify this parameter in the backup_dest_option configuration item, the value of the cluster-level configuration item backup_recovery_window is used by default. If you do not specify either backup_dest_option or backup_recovery_window, the default value 0 is used, indicating that backup data will never expire. We recommend that you use backup_dest_option to specify the retention period of backup data.

     When the backup expires, the system automatically clears it based on preset rules.

   • auto_delete_obsolete_backup specifies whether to automatically delete expired backup data.

     If you do not specify this parameter in the backup_dest_option configuration item, the value of the cluster-level configuration item auto_delete_expired_backup is used by default. If you do not specify either backup_dest_option or auto_delete_expired_backup, the default value false is used, indicating that expired backup data will not be automatically deleted. In this case, auto_delete_obsolete_backup must be set to true. We recommend that you use backup_dest_option to specify whether to automatically clear expired backup data.

   • log_archive_piece_switch_interval specifies whether to automatically split the content of the log file directory into multiple directories based on a specific interval. The default value is 0, indicating that no splitting is performed. The valid value range is [1d,7d].

   • backup_copies specifies how many copies of backup data must be retained for backup redundancy. The default value is 1. If you have specified backup_backup_dest, we recommend that you set backup_copies to 2. The valid value range of backup_copies is [1,8].

     If you set backup_copies to 1, the system deletes backup data without considering whether its secondary backup is successful. If you set backup_copies to 2, the system will only automatically delete backup data in backup_dest after its secondary backup has been saved to backup_backup_dest.

   For more information about backup_dest_option, see the "backup_dest_option" topic in Reference Guide (MySQL Mode) or Reference Guide (Oracle Mode).

Enable automatic data clearing by using the auto_delete_expired_backup configuration item

The cluster-level configuration item auto_delete_expired_backup can also be used to enable automatic clearing. We recommend that you use backup_dest_option to enable automatic clearing.

1. Log on to the database as the root user of the sys tenant.

2. Run the following command to set the expiration time of backup data by using the backup_recovery_window configuration item.

   obclient>ALTER SYSTEM SET backup_recovery_window = <expiration time>;
   

   backup_recovery_window specifies the time window in which a backup can be restored. The default value is 0, which indicates permanent retention. We recommend that you set this parameter to '7d' so that the backup will be retained for one week. When the backup expires, the system automatically clears it.

   Example:

   obclient> ALTER SYSTEM SET backup_recovery_window = '7d';
   

3. Run the following command to enable automatic clearing of backup data by using the auto_delete_expired_backup configuration item.

   obclient> ALTER SYSTEM SET auto_delete_expired_backup = 'True';
   

   Note

   If a 9044 error is reported, the data clearing task is ongoing and you are not allowed to initiate another clearing task.