What is RMAN incremental backup

This article introduces the knowledge of "what is RMAN incremental backup". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

I. incremental backup

1. Options for incremental backup

Establishing an incremental backup is very simple, essentially specifying a parameter INCREMENTAL LEVEL=n, which can be added when you execute the BACKUP command. Incremental backups can create two levels, and the number 0.. n means (n up to no more than 4). Usually we only specify level 1 backup and level 1 backup. Starting from level, all incremental backups must first create a level backup, which is equivalent to a full backup of the database.

It is important to note that a full backup is also performed through BACKUP DATABASE, but such a full backup is not the same as a level backup in an incremental backup (although it is a full backup of a database), because a regular full backup does not include an incremental backup strategy and does not support the creation of incremental backups based on it.

(1) create a full database backup with incremental backup level

RMAN > backup incremental level=0 database

(2) create a level 1 backup for the data file users01.dbf

RMAN > backup incremental level=1 datafile'/ u01qqappActionoradataUniple users01.dbf'

(3) create a backup with an incremental level of 1 for the tablespace

RMAN > backup incremental level=1 tablespace users

two。 Incremental backup Typ

Incremental backups provide two types of backups, DIFFERENTIAL (differential) and CUMULATIVE (cumulative). The specific difference is not detailed here. By default, incremental backups created by RMAN are DIFFERENTIAL (differential backups). If you want to establish a CUMULATIVE (cumulative backup), you need to specify whether to execute the BACKUP command

Eg: RMAN > backup incremental level=1 CUMULATIVE database

Second, whether to choose incremental backup

The incremental backup of RMAN can not only reduce the backup set size, but also improve the backup efficiency and save backup time. However, it is important to realize that although the backup time may be cut and the backup set size may be reduced, the time required to perform a restore operation may increase because the database needs to read multiple backup sets to complete the restore operation. So in order to reduce the recovery time, incremental backup should be used with caution!

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