1 2 Previous Next 17 Replies Latest reply: May 20, 2013 1:54 AM by Mahir M. Quluzade RSS

    RMAN confusions

    yxes2013
      Hi all,

      10gR2

      I hate my RMAN backup because it took soooo long and I so big even if its only 4GB data. It seems mirroring 4 times. :(

      Can you tell me which parameter causes it to do so? How can I make it faster and smaller size?
      RMAN> run {
      2> show all;
      3> }
      4>
      using target database control file instead of recovery catalog
      RMAN configuration parameters are:
      CONFIGURE RETENTION POLICY TO REDUNDANCY 3;
      CONFIGURE BACKUP OPTIMIZATION OFF; # default
      CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
      CONFIGURE CONTROLFILE AUTOBACKUP OFF;
      CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
      CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
      CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
      CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
      CONFIGURE MAXSETSIZE TO UNLIMITED; # default
      CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
      CONFIGURE ENCRYPTION ALGORITHM 'ABC128'; # default
      CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
      CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u01/oracle/product/10.2/db_1/dbs/snapcf_SDB.f'; # defaulT
      Thanks a lot,
        • 1. Re: RMAN confusions
          Alvaro
          Are you backing up to TAPE or DISK ?

          Post your Backup script so we can see if you are performing any duplexing, becase in your persistent configuration you are not duplexing anything:
          CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
          CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
          If you are performing incremental backups, consider using Block Change Tracking feature, it can save a lot of RMAN work.
          • 2. Re: RMAN confusions
            Aman....
            May be you want to read the RMAN Tuning from the docs,
            http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmtunin.htm#CACJCBDB

            Aman....
            • 3. Re: RMAN confusions
              yxes2013
              Thanks all,

              I am only backing up on disk, and I use the above parameters listed.


              How about changing:
              CONFIGURE RETENTION POLICY TO REDUNDANCY 3;
              to redundancy 1, whould the backupset get smaller?
              • 4. Re: RMAN confusions
                yxes2013
                Hi all,

                Will encryption causing the backup to slow? How do I set this pamater to a faster value?
                CONFIGURE ENCRYPTION ALGORITHM 'ABC128';
                Thanks,
                • 5. Re: RMAN confusions
                  Alvaro
                  yxes2013 wrote:
                  Thanks all,

                  I am only backing up on disk, and I use the above parameters listed.


                  How about changing:
                  CONFIGURE RETENTION POLICY TO REDUNDANCY 3;
                  to redundancy 1, whould the backupset get smaller?
                  No, it wouldn't.

                  That is your retention policy. RMAN will decide which backupsets are obsolete based on that.

                  In your current setup, RMAN is keeping at least 3 copies of each datafile on disk, for example if you backup once during the day then:

                  1. Monday 1 copy
                  2. Tuesday 2 copies
                  3. Wednesday 3 copies.
                  4. Thursday - After completion of this backup, your monday one becomes obsolete and RMAN may now delete it in case it needs space on the FRA.

                  So changing the redundancy policy will only affect how far back you can recover the database, NOT the speed of your backup.

                  Please post your backup script.
                  • 6. Re: RMAN confusions
                    Mahir M. Quluzade
                    yxes2013 wrote:
                    Thanks all,

                    I am only backing up on disk, and I use the above parameters listed.


                    How about changing:
                    CONFIGURE RETENTION POLICY TO REDUNDANCY 3;
                    to redundancy 1, whould the backupset get smaller?
                    Hi,

                    you can change redundancy to 1 as
                     
                     RMAN> CONFIGURE RETENTION POLICY TO REDUNDANCY 1;
                     RMAN> SHOW RETENTION POLOCY;
                    As you know, retention policy is control your backups for obsolete, not size.

                    If you are using encryption, then RMAN using Encryption Algorithm.
                    You can explicitly override the persistent encryption configuration for an RMAN session with the following command:
                     RMAN>SET  ENCRYPTION ON;
                    If encryption disabled, then not effect any effect on backup.

                    See more :http://docs.oracle.com/cd/B28359_01/backup.111/b28270/rcmconfa.htm

                    Regards
                    Mahir M. Quluzade
                    • 7. Re: RMAN confusions
                      yxes2013
                      I thank you all,

                      this is my backup script:
                      run {
                      crosscheck archivelog all;
                      delete noprompt expired archivelog all;
                      backup database;
                      SQL 'ALTER SYSTEM ARCHIVE LOG CURRENT';
                      BACKUP ARCHIVELOG ALL;
                      delete obsolete;
                      }
                      Can you please inject some parameters to make it faster?
                      Maybe some defaults should be changed?

                      Thanks,
                      • 8. Re: RMAN confusions
                        Rob_J
                        Hi,

                        Looks like you will only be using one channel to do the backup. You should think about:

                        1. What time of the day does it run? Outside of peak load?
                        2. Are there spare resources for disk and CPU when the backup runs?
                        3. How long does it currently take and what size is the DB? You said 4GB, is that correct?

                        It looks like you are just doing a full database backup without any incremental backups? Here is what I do for a level 0 backup as part of an incremental backup strategy.
                        run
                        {
                          ALLOCATE CHANNEL c1 DEVICE TYPE DISK FORMAT 'D:\rman_level0\%d_%T_%s_%t';
                          ALLOCATE CHANNEL c2 DEVICE TYPE DISK FORMAT 'D:\rman_level0\%d_%T_%s_%t';
                          ALLOCATE CHANNEL c3 DEVICE TYPE DISK FORMAT 'D:\rman_level0\%d_%T_%s_%t';
                          ALLOCATE CHANNEL c4 DEVICE TYPE DISK FORMAT 'D:\rman_level0\%d_%T_%s_%t';
                          BACKUP AS COMPRESSED BACKUPSET INCREMENTAL LEVEL = 0 DATABASE PLUS ARCHIVELOG NOT BACKED UP 1 TIMES;
                        }
                        Obviously the disk locations and how many channels (the level of paralellism you want to use) will need to be changed to suit your environment. Backing it up as compressed should mean it is around 20% of the total size of your database but it will use more CPU and take longer. Test it out first.

                        Here are some more notes on a complete [url http://www.ora00600.com/wordpress/articles/oracle-rman-backup-recovery/]RMAN backup strategy, part way down the page.

                        Hope that helps,
                        Rob
                        • 9. Re: RMAN confusions
                          yxes2013
                          Yes the raw data when I run expdp is just 4Gb and the expdp runs only 5 minutes while the RMN backup set and archivelogs have 15G total and took more than 30 mins. It seems generating redundant backup sets and acrhivelogs? I only want 1 copy each. and delete obsolete rightaway so my flash recovery will not ran out of space.

                          How do I know if it is making duplicate copies?


                          Thanks....
                          • 10. Re: RMAN confusions
                            Vinod Dhandapani
                            Configure Archivelogs deletion policy.

                            CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO DISK;

                            Thanks
                            Vinod
                            • 11. Re: RMAN confusions
                              DK2010
                              Hi

                              Check this for improve RMAN performnace it may help you

                              http://docs.oracle.com/cd/B28359_01/backup.111/b28270/rcmtunin.htm
                              • 12. Re: RMAN confusions
                                yxes2013
                                Hi Vin,
                                CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO DISK;
                                How is the above different from the one below given by RobJ?
                                BACKUP AS COMPRESSED BACKUPSET INCREMENTAL LEVEL = 0 DATABASE PLUS ARCHIVELOG NOT BACKED UP 1 TIMES;
                                Thanks,

                                Edited by: yxes2013 on 16.5.2013 21:26
                                • 13. Re: RMAN confusions
                                  Mahir M. Quluzade
                                  Hi,
                                  >
                                  CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO DISK;
                                  It is configure archived log deletion policy of RMAN configuration.
                                  If you configure deletion policy as this command, then when you delete archive logs and
                                  archived logs is not backed up then RMAN is don't delete this archivelog files.
                                  How is the above different from the one below given by RobJ?
                                  BACKUP AS COMPRESSED BACKUPSET INCREMENTAL LEVEL = 0 DATABASE PLUS ARCHIVELOG NOT BACKED UP 1 TIMES;
                                  It is only backup command. It means, backup database inc level 0 compressed and also backup archived log which is didn't backed up 1 time.

                                  Mahir
                                  • 14. Re: RMAN confusions
                                    yxes2013
                                    Hi again,

                                    Supposing I will mixed the parameters you provided to my existing rman script like:
                                    run
                                    {
                                      ALLOCATE CHANNEL c1 DEVICE TYPE DISK FORMAT 'D:\rman_level0\%d_%T_%s_%t';
                                      ALLOCATE CHANNEL c2 DEVICE TYPE DISK FORMAT 'D:\rman_level0\%d_%T_%s_%t';
                                      ALLOCATE CHANNEL c3 DEVICE TYPE DISK FORMAT 'D:\rman_level0\%d_%T_%s_%t';
                                      ALLOCATE CHANNEL c4 DEVICE TYPE DISK FORMAT 'D:\rman_level0\%d_%T_%s_%t';
                                      CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO DISK;
                                      BACKUP AS COMPRESSED BACKUPSET INCREMENTAL LEVEL = 0 DATABASE PLUS ARCHIVELOG NOT BACKED UP 1 TIMES;
                                      SQL 'ALTER SYSTEM ARCHIVE LOG CURRENT';
                                      crosscheck archivelog all;
                                      delete noprompt expired archivelog all;
                                    }
                                    Would it be better ?

                                    Thanks...
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