Re: Rman question - recover after a delete obsolete?

Hi Dave,

shoad316_at_hotmail.com (Dave) wrote in message news:<78cf0572.0403011422.d1c4d7_at_posting.google.com>...
> Hi,
>
> Currently we backup our 8.1.7 and 9.2.0.2 databases using RMAN to
> disk. WE have a retention policy of 1. Since the filesystem is
> backed up to tape nightly, before we run the next backup we remove the
> old rman backup.

You mean that your retention policy is configured to redundancy=1, isn't it?

>
> Some of the DBA's run a delete obsolete in their nightly routine but I
> haven't because i'm not actually sure of the consequences. Lets say
> there's a problem and a user requests a copy of the database from 2
> weeks ago. If the retention was 1 and a delete obsolete was executed
> will we be able to recover using the catalog? My gut tells me no
> because were deleting all information about the backup from the
> catalog.

You're right, and you couldn't manually catalog the backups after you restore them from tapes.
If the retention policy for the catalog itself is less restrictive, you could perhaps restore it at the date at which these backups were known, but I'm not sure it would work as easily.

>
> I'd rather disable the retention policy within rman.. Then if we had
> to restore from a few weeks previous all you would have to do is run a
> crosscheck.

It's a solution but your RMAN catalog will keep growing uselessly and will not reflect the real availability of your backups. The reporting commands would be of little use.

You should determine your retention needs precisely for each DB. Configure RMAN accordingly, probably by specifying recovery windows. Then, since you don't have any media manager within RMAN, make sure that your backup group's tape retention policy is compatible with that. They must keep *at least* as many backups as needed by your retention policy.
Beware that if they use a retention policy based on the age of backups, it won't be directly compatible with RMAN recovery windows. You'll have to study that point.

Then you could run 'delete obsolete' daily with the 'force' option, since RMAN would complain otherwise (the obsolete backups will not be on disk).

>
> We don't backup directly to tape, we don't have enough disk space to
> hold enough backups for the retention users require so we rely on the
> backup group's tape retention policy to satisfy our needs. So say
> nightly we run a backup, then a delete obsolete and 2 days from now
> need to restore, even tho we have restored the datafiles from tape
> will we be able to reocover? Would the recover process be different?
> Should we be marking backups as keep or disable the retention policy
> in rman?
>
> Thanks
Received on Thu Mar 04 2004 - 03:19:27 CST