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Former Member

Online Backup is needed everyday??

Hello All,

For our ECC 6.0 System,OS=HP UNIX,Database=Oracle 9i

We are taking only Offline backup everyday...No Online backup is taken.Can we restore the system completely if it crashes??Is there any necessity to take the Online Backup daily??But we are taking File system Backup everyday from HP-Unix.What startegy is followed for SAP Best practise??

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    Former Member
    Dec 15, 2009 at 02:28 AM

    Hi,

    back into the purpose of the backup : enable to restore data to its latest stable condition while system or database is crashed.

    backup offline : you can restore database back only until the latest offline backup.

    say you are doing the last offline backup on Dec 1, 2009, so if your system is crash now, you can only bring your system back to Dec 1, 2009. No matter if you are have full-set of archivelog, it will useless.

    backup online : you can restore database back until the last archivelog you can save before crash.

    say you are doing the last online backup this morning and regularly backup your archive log, so if your system is crash now, you can restore your online backup followed by applying your saved archivelog to bring your database to the latest condition (equivalent to the last archivelog you have). say the last online backup is 5AM this morning, and you backup archivelog every hour, and on on 7.15AM system is crash, you can restore online backup taken on 5AM, plus restoring (applying) archivelog on 6AM and 7AM, and then bring your database up. in this case, you may lost data from 7AM to 7.15AM if archivelog created during this time can't be save (during system/database crash). if you have enough time to save archivelog created between 7AM and 7.15AM, you can prevent or minimize data loss.

    suggestion for you :

    offline backup : once a week

    online backup : once a day

    archivelog oracle backup : every hour (or depends on how many archivelog created per hour on your system)

    filesystem (vg00 or internal disk) backup : once a month, before applying patch and after applying patch

    compared to our system:

    offline backup : once a month (due to huge database we have)

    online backup : once a day

    archivelog oracle backup : every hour

    filesystem (vg00 or internal disk) backup : once a month, before applying patch and after applying patch

    remember, online backup without archivelog backup (on Oracle system) is nothing.

    and filesystem (vg00 or internal disk) backup (usually using ignite backup) is important to maintain stable version of filesystem (vg00 or internal disk) which contain OS (HPUX) and other important files not stored on external storage.

    hope it help you,

    rgds,

    Alfonsus Guritno

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    Former Member
    Dec 14, 2009 at 08:18 PM

    Hi,

    Offline backups are usefull in some cases, like a major Oracle upgrade, however, especially in production, downtime is not always afforsable by the business. The common practice is to use online database backups (combined with filesystem backups for non-database filesystems). With online backups you rely on backups of the archived redologs for recovery.

    A daily online backup is preferred (recommended by SAP). Traditional online backups to tape are common although as the database gets bigger so does the time to complete a backup. You might want to take full backups of your production database maybe every other week and rely on archived redologs for recovery.

    It is important to test your backup and the time it would take to restore to a point in time in order to decide on the frequency of the backups.

    If resources are available you might consider mirror backups or snapshot backups (storage technology) in the future to shorten the backup runtime.

    --Noe

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    Former Member
    Dec 14, 2009 at 08:26 PM

    Ashley,

    I would recommend you to go through following:

    SAP [Note 842240 - FAQ: Backup strategy of large and highly-available databases].

    [http://help.sap.com/saphelp_nw70/helpdata/en/1a/8fdd5a3f4a234ca4523afcb2def16d/frameset.htm]

    Online backup will help you to keep your production system available to users. That is the reason during week days online backup is recommended. You need to schdule Archive log backup regularly when online backup is scheduled.

    Offline backup you could schedule once a week during weekend.

    Backup strategy depends upone infrastructure you have and requiremnet of availability of your system.

    Best Luck,

    Digesh Joshi

    Edited by: digeshjoshi on Dec 14, 2009 2:48 PM

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    • Former Member

      Hi,

      As mentioned earlier offline backups is not an ideal backup solution considering the SAP system has to be unavailable for the duration of the backups.

      The suggestion would be to have online backups daily and hourly archive logs( or change based on your business requirement).

      The offline backups can be done weekly during weekends when the business can afford the outage.

      There are technologies mentioned earlier to do snapshot backups, mirrors, log shipping which can be used as alternates but needs to be analyzed for your environments needs and best fit.

      Cheers Sam

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    Former Member
    Dec 15, 2009 at 07:08 AM

    Hello Ashley,

    Assuming the DB is Oracle.

    Offline back up is consistent so it can be restored in case of a crash. However this issue is if you crash occurs say at 10:00 AM and the backup time stamp was 2 A.M then you loose 8 hrs of data!. Of course if you have the latest backup of archivelogs available along with control file back up later than the offline backup time stamp you can roll forward your database while doing oracle recovery. You need to start the database with the latest backup of control files and not the ones backed up with the offline backup. If you use the later set of control files oracle won't allow you to do any further recovery (to the the point recovery) since the offline back is consistent with consistent SCNs across the control files and data file headers.

    But as suggested by other before me you must go for online backup. That is the recommended way.

    Regards.

    Ruchit Khushu

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    Former Member
    Dec 15, 2009 at 07:08 AM

    Hello Ashley,

    Assuming the DB is Oracle.

    Offline back up is consistent so it can be restored in case of a crash. However this issue is if you crash occurs say at 10:00 AM and the backup time stamp was 2 A.M then you loose 8 hrs of data!. Of course if you have the latest backup of archivelogs available along with control file back up later than the offline backup time stamp you can roll forward your database while doing oracle recovery. You need to start the database with the latest backup of control files and not the ones backed up with the offline backup. If you use the later set of control files oracle won't allow you to do any further recovery (to the the point recovery) since the offline back is consistent with consistent SCNs across the control files and data file headers.

    But as suggested by other before me you must go for online backup. That is the recommended way.

    Regards.

    Ruchit Khushu

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