Forum Stats

  • 3,874,714 Users
  • 2,266,767 Discussions
  • 7,911,959 Comments

Discussions

RMAN : Change default Autobackup Controlfile to ON and have a Default Autobackup RETENTION POLICY

ritan2000
ritan2000 Member Posts: 20 Bronze Badge
edited May 15, 2016 8:30PM in Database Ideas - Ideas

I'm Oracle University Instructor and each time I read in the Slides about RMAN  : "configure autobackup controlfile ON -> Oracle Strongle Recommend it", I ask myself why is  OFF by default?

In my opinion should be ON by DEFAULT, and  I though the problem could be purging autobackups. So,it could have a purge policy by default.

Example :

CONFIGURE CONTROLFILE AUTOBACKUP ON;

CONFIGURE RETENTION POLICY AUTOBACKUP CONTROLFILE TO REDUNDANCY  3;

I think to purge you could use the same algorithm that is used in RAC to purge automatic backups of OCR.

Using for purging the pathname default that exists in autobackup format.

CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; 

ritan2000Diego AguirreLothar FlatzctriebN.B.
6 votes

Active · Last Updated

Comments

  • top.gun
    top.gun Member Posts: 3,666 Gold Crown

    I'd agree the issue is purging, as I encountered a situation before where the autobackups filled the disk.

    I think it's off by default because for an environment that's in noarchivelog mode that doesn't get backed up (ie a sandpit environment), the autobackups aren't useful so you don't want them to fill the disk.

  • I agree. it would be usefull

  • ctrieb
    ctrieb Member Posts: 314 Gold Trophy

    Yes, I think it's a good to change the default entries, because the advanatage of this will be better, than the disadvantages.

    ritan2000
  • top.gun
    top.gun Member Posts: 3,666 Gold Crown

    Don;t forget the default is no backups, and no purging of backups.

    So making the autobackup enabled as the default carries some risk of filling the disk.

  • ritan2000
    ritan2000 Member Posts: 20 Bronze Badge

    Don;t forget the default is no backups, and no purging of backups.

    So making the autobackup enabled as the default carries some risk of filling the disk.

    Hi top.gun :

      I fell you so worry about filling the disk, but I think Oracle have a lot of technology to avoid this.

    Oracle has implemented  PURGE in several functions, for example :

    - in RAC to purge automatic backups of OCR

    - in ADRCI to purge de traces and logs

    so, Oracle has differents algorithms to think which one could use in this case.

  • top.gun
    top.gun Member Posts: 3,666 Gold Crown

    Hi top.gun :

      I fell you so worry about filling the disk, but I think Oracle have a lot of technology to avoid this.

    Oracle has implemented  PURGE in several functions, for example :

    - in RAC to purge automatic backups of OCR

    - in ADRCI to purge de traces and logs

    so, Oracle has differents algorithms to think which one could use in this case.

    Backups are not purged by default, and currently if you want to purge you need to do it manually.

    So Oracle would need to put in a default autopurge for the default autobackup, otherwise the controlfile backupsets will eventually filling the disk.

  • ritan2000
    ritan2000 Member Posts: 20 Bronze Badge

    Backups are not purged by default, and currently if you want to purge you need to do it manually.

    So Oracle would need to put in a default autopurge for the default autobackup, otherwise the controlfile backupsets will eventually filling the disk.

    Hi top.gun,

        I mentioned there are so many algorithms to implent if they want to implement this function.

    Also backups if you use FRA, Fast Recovery Area, has the way that control the space and do not fill the disk.

    https://docs.oracle.com/cd/B19306_01/backup.102/b14192/setup005.htm

    "Using a flash recovery area simplifies the ongoing administration of your database by automatically naming recovery-related files, retaining them as long as they are needed for restore and recovery activities, and deleting them when they are no longer needed to restore your database and space is needed for some other backup and recovery-related purpose"


    Regards,

    Rita


  • top.gun
    top.gun Member Posts: 3,666 Gold Crown

    Hi top.gun,

        I mentioned there are so many algorithms to implent if they want to implement this function.

    Also backups if you use FRA, Fast Recovery Area, has the way that control the space and do not fill the disk.

    https://docs.oracle.com/cd/B19306_01/backup.102/b14192/setup005.htm

    "Using a flash recovery area simplifies the ongoing administration of your database by automatically naming recovery-related files, retaining them as long as they are needed for restore and recovery activities, and deleting them when they are no longer needed to restore your database and space is needed for some other backup and recovery-related purpose"


    Regards,

    Rita


    Don't forget the FRA isn't enabled by default either, because Oracle can't know where to set it up by default (unless the Oracle home is the default location).

    The FRA needs to be enabled first.