8 Replies Latest reply: Mar 1, 2010 4:30 PM by jgarry RSS

    REDUCE THE BACKUP TIME/RMAN

    756823
      I am taking full backup every week end. But its taking a long time to complete as size of database is very big. Is ther any way to do backup fastly as parrallal processing . We are using RMAN. Kindly tell me some way.
        • 1. Re: REDUCE THE BACKUP TIME/RMAN
          P.Forstmann
          See Tuning Backup and Recovery in http://download.oracle.com/docs/cd/B19306_01/backup.102/b14191/rcmtunin.htm#i1006104 in general and possibly RMAN Incremental Backups in http://download.oracle.com/docs/cd/B19306_01/backup.102/b14192/bkup004.htm#BRBSC133.
          • 2. Re: REDUCE THE BACKUP TIME/RMAN
            EdStevens
            user9231434 wrote:
            I am taking full backup every week end. But its taking a long time to complete as size of database is very big. Is ther any way to do backup fastly as parrallal processing . We are using RMAN. Kindly tell me some way.
            SEveral methods in the rman guide (see tahiti.oracle.com) and also in "Oracle Database RMAN Backup & Recovery" by Hart and Freeman (Oracle Press). Depending on your needs, a couple of things come to mind immediately, and they are not mutually exclusive:

            1 - take a full (incremental 0) backup only once a week, with incremental (incremental 1) backups the other 6 days.

            2 - backup only a subset of your tablespaces each day - different subset each day.

            3 - implement change tracking, so rman only backs up blocks that have actually been modified


            Also be aware
            - you don't mention down time ... are you taking a cold backup? Are you aware that rman can do a hot backup, so you don't have to stop the database? Performance impact is usually pretty minimal.

            - you must be in archivelog mode for any of the above.
            • 3. Re: REDUCE THE BACKUP TIME/RMAN
              756823
              Thanks for your reply, As our database running 24/7, I could do hot backup only. As you said , I take incremental level 0 backup at weekend only. This full backup only taking around 3 hours. I want to decrease the full backup time only.
              • 4. Re: REDUCE THE BACKUP TIME/RMAN
                EdStevens
                user9231434 wrote:
                Thanks for your reply, As our database running 24/7, I could do hot backup only. As you said , I take incremental level 0 backup at weekend only. This full backup only taking around 3 hours. I want to decrease the full backup time only.
                Ok, now we have a better understanding of where you are and exactly what you need to achieve. You've already been pointed to the relevant references. I just wanted to make sure you were 'asking the right question'. ;-)
                • 5. Re: REDUCE THE BACKUP TIME/RMAN
                  611900
                  There can be multiple level of contention in the case of backup.

                  You fist need to see where which section of the backup is making it slow.

                  1. Check the database. if you are not using Automatic Memory Mgmt then give Large Pool enough space to handle RMAN request.
                  2. Configure multiple RMAN Channels if possible.
                  3. Check the thoughput you are getting at the tape level (TSM in case you are using it)

                  Some time the thoughput at the TSM level is so low that no matter how much you tune your RMAN/Database, it won't help. I am sure I may be missing few other points that other members might have pointed out.
                  • 6. Re: REDUCE THE BACKUP TIME/RMAN
                    756823
                    Is is possible to make parrallel processing in morethan one disk or tape at the same time?
                    • 7. Re: REDUCE THE BACKUP TIME/RMAN
                      sb92075
                      Is is possible to make parrallel processing in morethan one disk or tape at the same time?
                      How many disk controllers?
                      How many tape controllers?

                      Bottleneck will occur at slowest device; regardless of number of parallel streams feeding it.

                      Edited by: sb92075 on Mar 1, 2010 10:11 AM
                      • 8. Re: REDUCE THE BACKUP TIME/RMAN
                        jgarry
                        sb92075 wrote:
                        Is is possible to make parrallel processing in morethan one disk or tape at the same time?
                        How many disk controllers?
                        How many tape controllers?

                        Bottleneck will occur at slowest device; regardless of number of parallel streams feeding it.
                        With the built-in cache many modern devices have, this can sometimes be elsewhere than expected. Don't be afraid to try it even if it looks like it might not work or a rule of thumb tells you it won't.

                        Also be sure and stress-test - many of these devices will work fine until they hit a certain saturation, then go downhill fast just cause a little extra work started by, say, OS housekeeping.