When Database backup (DBS) performs a backup task on a database, the database performance is affected. Therefore, we recommend that you perform backup tasks during off-peak hours. This topic describes the backup principle, impact, and usage notes.
Backup principle and impact
Item | Logical backup | Physical backup |
Full backup | DBS splits the data of all tables in a database and executes SQL statements on the database to read the data in multiple threads in parallel. | A DBS backup gateway is installed on the server of a database for database backups. |
Incremental backup | DBS incrementally backs up logs stored in the memory of a database in real time. This prevents the sudden I/O performance drop that may occur when a large amount of data is backed up at a time. | |
Impact on databases | Data is read from a database instance, which affects the database performance. However, no tables are locked during a logical backup. | Data is read from the disks of a database, which affects the I/O performance of the database. However, no tables are locked during a physical backup. |
Usage notes
We recommend that you perform backup tasks during off-peak hours.
DBS allows you to adjust the backup speed. You can mitigate the impact of backups on database performance by reducing the number of threads that are used to back up data in parallel. For more information, see How do I change the maximum backup speed?
In scenarios in which a primary database and a secondary database are used, we recommend that you perform backup tasks on the standby database if you have access to the standby database.
NoteIf you use ApsaraDB RDS databases, only the primary ApsaraDB RDS database is accessible. Therefore, you can perform backup tasks only on the primary ApsaraDB RDS database.
References
For more information about the differences between logical backup and physical backup, see Logical backup, physical backup, and snapshot.