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6 Replies Latest reply: Dec 25, 2012 4:01 AM by tychos RSS

what difference between  incremental level = 0  and full backup

proora Newbie
Currently Being Moderated
Hello World ,

see the below RMAN script , as shown is incremental level 0 and the script run every night to take the backup and we are using 7 taps to take the backup which everyday has its own tape , if i take the backup as increment , do i need one tape to do recovery to all of them?

run {
allocate channel ch1 type 'sbt_tape'
PARMS="BLKSIZE=262144,ENV=(CV_mmsApiVsn=2,CV_channelPar=ch1)"
TRACE 0;
setlimit channel ch1 maxopenfiles 8;
backup
incremental level = 0
filesperset = 32
database
include current controlfile ;
}
  • 1. Re: what difference between  incremental level = 0  and full backup
    tychos Expert
    Currently Being Moderated
    Hi proora,
    what difference between incremental level = 0 and full backup
    On an incr level 0 you can run incr level 1 backups but on a full backup you can't.
    Reading your post you state you run a incr level 0 every day which defeats the purpose of an incremental strategy.
    You could run a inc level 0 once (or twice) a week but you need to retain these backups for a longer period of time.
    For example for a weekly cycle you need the last two level 0 backups plus the daily level 1 backups.
    Rgds,
    Tycho
  • 2. Re: what difference between  incremental level = 0  and full backup
    mseberg Guru
    Currently Being Moderated
    Hello;


    A full backup is a backup that includes every allocated block.


    An incremental backup level 0 includes all the blocks except those blocks compressed because they have never been used.


    An incremental backup level 1 includes only those blocks that have changed since the parent backup.



    A full backup won't work will an incremental backup level 1 because a full backup does not keep track of SCN and blocks the way an incremental backup level 1 does.
    So if you run an incremental backup level 1 next after a full backup, RMAN will force a level 0 backup.


    Best Regards

    mseberg
  • 3. Re: what difference between  incremental level = 0  and full backup
    Pinela Journeyer
    Currently Being Moderated
    Hi,

    Just adding to what has already been said....
    and specifying to your "need 1 more tape".

    you can think of your incremetal backups just like your archivelogs (just think). when you recover from a full backup you need to apply the generated archivelogs up to the time of the desired recover.
    ok.
    so, if you run incrementals, to restore/recover up to a specific point, you will need.
    - backup inc level 0,
    - backup inc level 1 (number depends on if they are cumulative or differetial (more on this later)).
    - and the number of archivelogs generated

    now, differential vs cumulative (http://docs.oracle.com/cd/B19306_01/backup.102/b14192/bkup004.htm).
    summary:
    - a level 1 differential incremental takes the blocks altered from the last level 0 or level 1 backup
    - a level 1 cumulative incremental takes the blocks altered from the last level 0 backup

    hope it helps,
    br,
    jpinela.
  • 4. Re: what difference between  incremental level = 0  and full backup
    proora Newbie
    Currently Being Moderated
    Think you all,
    i really appreciate what you mentioned ,
    if i do daily backup and each day i am using different tape , my question is if i am plan to do recovery to DR site , i need to use the last tape of all more than that?
  • 5. Re: what difference between  incremental level = 0  and full backup
    Pinela Journeyer
    Currently Being Moderated
    hi,

    you will need all the tapes, that have the necessary incremental level 0 and most recent level 1 backups.
    so if these are in different tapes, then, yes.

    br,
    jpinela.

    p.s. - if you think any comment is helpful or correct, please mark them as such.
    thank you.

    Edited by: Pinela on Dec 24, 2012 11:14 AM
  • 6. Re: what difference between  incremental level = 0  and full backup
    tychos Expert
    Currently Being Moderated
    Hi proora,
    First thing is mesberg is right if you do a full backup and than proceed with incremental level 1 the first inc after the full will be a level 0.
    So rman will work.
    if i am plan to do recovery to DR site , i need to use the last tape of all more than that?
    Based on the information you provided you only backup data files and no archive logs.
    Are you doing hot or cold backups?
    If you do hot backups you need to adjust your backup scrips to include archive logs.
    If you keep the current strategy of a full every day you should be able to only do the restore using the last tape.
    I would advice you to test your DR.
    Regards,
    Tycho

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