Re: rman crosscheck question

From: Chuck <>
Date: Fri, 11 Apr 2008 16:44:11 GMT
Message-ID: <vzMLj.79$6w3.7@trnddc07>

hpuxrac wrote:
> On Apr 11, 10:20 am, Chuck <> wrote:

>> What would cause this with rman
>> I use Tivoli tdpo for my media manager. They provide a utility -
>> tdposync - which crosschecks backup pieces in the tdpo library against
>> the rman catalog to see if it has any that are no in the rman catalog.
>> It's sort of the inverse of rman's crosscheck.
>> Tdposync shows some backup pieces that it can't find in the rman
>> repository, so I go into rman and run "crosscheck backup". It finds
>> nothing wrong. I verify this by running "list expired backup" and it
>> lists nothing. I go back into tdposync and the backup pieces that it
>> listed 2 minutes prior are no longer listed.
>> Any ideas? Does rman crosscheck do more to the catalog than what is
>> listed in the documentation? Does it perhaps silently fix something?

> Can you create a reproducible test case? That might give some of here
> at cdos a better stab at helping you with your question.
> The crosscheck backup command will ( potentially ) make some changes
> to rows in v$backup_set ( maybe v$datafile_copy ) for a control file
> or rc_backup_set (etc) for a recovery catalog afaik mostly
> concentrating on the status codes ( available ... still valid in
> backup media or expired ).
> In general I think you should be driving from the rman side instead of
> the tivoli side. Perhaps your question can be submitted into tivoli
> support if you really need to use tdposync?
> Keeping a control file backup based catalog or a real recovery catalog
> healthy and useful by running crosscheck on a repeating/periodic basis
> ( varies by your requirements ) is potentially an area that you want
> to check out and maybe make some changes in how you are operating
> right now.

We are using catalog based backups. I agree that regular crosschecks keeps it healthy. That's why we *also* do tdposync which is essentially a crosscheck from the opposite perspective.

rman crosscheck ensures that everthing in the catalog is still available in the media library. It does nothing however for backup pieces in the media library that are not in the catalog. This can be caused by a failed backup where some of the pieces got written to the media manager but never got committed to the catalog. I've seen this if we run tdposync while an rman backup is still running. The completes backup pieces are not in the rman catalog but the media manager is fully aware of them.

tdposync takes care of this. It ensures that everything in the media library is also in the catalog. Received on Fri Apr 11 2008 - 11:44:11 CDT

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