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Thread: RMAN backups... archive logs, etc.

  1. #1
    I am using this as a basic level 0 bkp (I do level 1 on M-Sat)

    replace script hot_back0 {
    # Hot database level 0 whole backup
    allocate channel d1 type disk;
    allocate channel d2 type disk;
    incremental level 0
    skip inaccessible
    tag hot_level0
    filesperset 5
    # recommended format
    format '/integrate/BACK/RCAT/bc0_%U'
    (database include current controlfile);
    sql 'alter system archive log current';
    # backup all archive logs
    filesperset 20
    format '/integrate/BACK/RCAT/al0_%U'
    (archivelog all
    delete input);

    I have a question... I archive the current logs before I run this... and this script basically archives all archive logs.

    It then deletes them, correct? I'm just wondering why my archives disappear each day.

    Secondly, I am deleting redentant backups from the catalog...

    I first "report obsolete redundancy 2;" and then delete those.
    1. Am I correct that it doesn't delete required archives..
    2. When a level 0 backup is done... are the OLD archives required anymore (those made before the level 0)?
    3. Does RMAN (when deleting redundancies) remove those old archive logs because it no longer needs them?

    thanks... I'm just trying to get a better hold on where the archives go to... so if my database crashes.. and the recent archives are not there... and I open the database...

    I do a level 0 on Sun, level 1 on Monday.. DB crashes on Tues 11am and there are 2 new archives... the DB may need archives beyond the online redos (3 of them).
    The two recent archive logs are there... but any ones before those were put into the recovery catalog...

    How will I know if the DB requires more logs than are available on the file system when they are in the recovery catalog?



  2. #2
    Join Date
    Oct 2000
    Saskatoon, SK, Canada
    Answering to your questions, as per your script, the archive files were deleted from your arch directory, once they had been put in a file or backed up. Secondly, regarding the crash recovery, If your database were to crash, you would require the last level0 backup and the cumulative/level1-2 backups and the archives from the archive directory. If you are using the RMAN, RMAN would figure out what it needs from where. So, if I were to be asked about how long would it be better for one to hold on to the backup data, I would say atleast a month worth, but would be better 3 months of backups if your company requires.

    I know I not very clear, but this had been a case for me for a long time :o


    Life is a journey, not a destination!

  3. #3
    ok, so as long as I do not delete backups over 2 months old?

    I haven't deleted any backups since I started, however each 2 weeks I do run a script that deletes REDUNDANT backups.
    (backups that are redundant 2 times).

    > report obsolete redundancy 2;

    Since I do level 1 backups M-Sat and level 0 on Sun, you can see how a lot is deleted from the M-F backups as Sat has all of the changes since....

    but as for the archive backups and level 0 backups, I still have all of them...

    What the report I use to report backups older than say 2 months? As long as I have like 2 months of level 0's then I should be fine with removing and backups (data or archives) before then?


  4. #4
    and if I do a cold backup, then I can remove everything... and do a new level 0.


  5. #5
    Join Date
    Oct 2000
    Saskatoon, SK, Canada
    That is correct, but remove them only after making the cold backup. not before that.

    to check the old ones you can use

    report obsolete until time 'SYSDATE - your_time';

    If you want to make sure that you have atleast 2 redundant copies of recent backups then use

    report obsolete redundancy = 2 until time 'speculated_time';

    Hope this would help you to an extent.


    Life is a journey, not a destination!

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