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ORACLE INCREMENTAL BACKUP WITH EXAMPLE

ORACLE INCREMENTAL BACKUP

ORACLE INCREMENTAL BACKUP WITH EXAMPLE

  1. Taking backup of very large database (VLDB) will take time if the backup size is increasing frequently
  2. In such cases, we can go for incremental backup which will take backup of any changes happened from last full backup to till date
  3. Incremental backups are two types
    1. Differential (default)
    2. Cumulative
  4. Both incremental backup types will have level 0 and level 1 (level 0 –full backup, level 1-incremental backup)
  5. First time incremental backup will do level 0 backup always
  6. RMAN will perform incremental backup by identifying changed blocks with the help of block SCN
  7. We cannot recover database using level 1 backup applying on full database backup
  8. We can apply level 1 backup on image copies and can recover the database
  9. 10g RMAN can perform faster incremental backups using block change tracker. With this whenever any block changes CTWR (change track writer) background process will write that information to a tracking file
  10. The change tracking file resides in DB_CREATE_FILE_DEST

COMMANDS

# To take full backup in incremental mode

RMAN> backup incremental level 0 database;
RMAN> backup cumulative incremental level 0 database;

# To take differential backup

RMAN> backup incremental level 1 backup;

# To take cumulative backup

RMAN> backup cumulative incremental level 1 database;

# To enable change tracking

SQL> ALTER DATABASE ENABLE BLOCK CHANGE TRACKING;
You can also create the change tracking file in a location you choose yourself, using the following SQL statement:
SQL> ALTER DATABASE ENABLE BLOCK CHANGE TRACKING USING FILE ‘/mydir/rman_change_track.f’ REUSE;
The REUSE option tells Oracle to overwrite any existing file with the specified name.

# To disable change tracking

SQL> ALTER DATABASE DISABLE BLOCK CHANGE TRACKING;

# To apply incremental backup to datafile copy or level 0 backup

RMAN>RUN {
  RECOVER COPY OF DATABASE WITH TAG ‘incr_update’;
  BACKUP INCREMENTAL LEVEL 1 FOR RECOVER OF COPY WITH TAG ‘incr_update’
      DATABASE;
  }
View More:
STEPS FOR ORACLE CONTROFILE COMPLETE RECOVERY
ORACLE BACKUP DATABASE RECOVERY
ORACLE MISCELLANEOUS INTERVIEW QUESTIONS

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