246 - RMAN compression feature
When using the RMAN compression feature, you can choose among different compression algorithms.
You can query the view V$RMAN_COMPRESSION_ALGORITHM to view the compression algorithms available to you, as shown here :
| SQL> select algorithm_name, algorithm_description, is_default from v$rman_compression_algorithm; |
ZLIB : fast but little worse compression ratio
BZIP2 : good compression ratio but little slower
1. You can change the type on compression.
|
#rman target / nocatalog RMAN> show compression algorithm; RMAN configuration parameters for database with db_unique_name QA are: CONFIGURE COMPRESSION ALGORITHM 'ZLIB'; RMAN> show compression algorithm; RMAN configuration parameters for database with db_unique_name QA are: |
2. Start the rman commands
| rman target=/ << EOF CONFIGURE CONTROLFILE AUTOBACKUP ON; CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO ‘/(put backup directory here)/autobackup_control_file%F’; CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 30 DAYS; run { ALLOCATE CHANNEL D01 TYPE DISK MAXPIECESIZE 2047M; CROSSCHECK BACKUP; BACKUP AS COMPRESSED BACKUPSET DATABASE FORMAT ‘/(put backup directory here)/df_t%d_%u_%s_%T’; sql ‘ALTER SYSTEM ARCHIVE LOG CURRENT’; BACKUP AS COMPRESSED BACKUPSET ARCHIVELOG ALL FORMAT ‘/(put backup directory here)/al_%d_%u_%s_%T; BACKUP AS COMPRESSED BACKUPSET CURRENT CONTROLFILE FORMAT ‘/(put backup directory here)/control%d_%u_%s_%T’; CROSSCHECK BACKUP; DELETE NOPROMPT OBSOLETE; DELETE NOPROMPT EXPIRED BACKUP; RELEASE CHANNEL RMAN_BACK_CH01; } EXIT; EOF |
3. Ohters.
* By default, RMAN automatically names control file backups and stores them in the flash recovery area.
To configure RMAN to write control file backups to the /< dir A> directory :
( %F will generate a unique filename)
| RMAN> CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/< dir A >/cf%F'; |
* Ensure that RMAN retains all backups needed to recover the database to any point in time in the last 7 days :
| RMAN> CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS; |
* Retain three backups of each datafile :
| RMAN> CONFIGURE RETENTION POLICY TO REDUNDANCY 3; |
* Delete backups no longer required by the retention policy:
| RMAN> DELETE OBSOLETE |
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