DBS offers features such as full backup, incremental backup, and data restore. This topic describes the differences between DBS backup methods and how to select a backup method.
|Logical backup||Backs up database objects such as tables, indexes, and stored procedures by using utilities such as MySQL mysqldump and Oracle exp/imp.|
|Physical backup||Backs up database files on the operating system by using utilities such as MySQL XtraBackup and Oracle RMAN.|
|Snapshot backup||Provides a fully available copy of a specified data set based on the snapshot technology by using utilities such as Veritas File System (VxFS), Linux Volume Management (LVM), and NetApp NAS. You can choose only to maintain snapshots on the local machine, or back up snapshots across hosts.|
|Backup method||Principle||Characteristics||Supported by DBS|
|Logical backup||1. Full backup: Split the data of each table, and run SQL statements on the database to read data in multiple paralleled threads.
2. Incremental backup: Capture logs in the database memory in real time, and adjust the log reading speed according to the log generation speed of the database.
|1. Full backup: Data is stored on disks. Reading data has a negative impact on the I/O performance of the database. However, full backup does not lock the database. Therefore, its impact on database performance is limited.
2. Incremental backup: Database logs are stored in the database cache. Incremental backup is performed in real time, and only a small number of logs are backed up each time. Therefore, log reading has a very small impact on the I/O performance of the database.
|Physical backup||1. Full backup: To perform a full backup operation, you must first install a DBS backup gateway on the server where your database is hosted. Then, the backup gateway will help you back up your database to OSS.
2. Incremental backup: The principle is the same as that of incremental backup when the logical backup method is used.
|1. Full backup: Copy files from the operating system. The backup speed is faster than that of logical backup.
2. Incremental backup: The characteristics are the same as those of incremental backup when the logical backup method is used.
|Partially supported (DBS does not support physical backup of RDS databases. The reason is that you must install a backup gateway to run a physical backup task. However, RDS databases do not provide access to the operating system. As a result, you cannot install the backup gateway.)|
For more information about the restrictions for using DBS to perform physical backups, see Physical backup.
DBS supports logical backup and physical backup. It does not support snapshot backup for the time being.
|Backup method||Applicable database size||Support backup of RDS||Require backup gateway|
|Logical backup||MBs to hundreds of GBs||Yes||No|