Re: RMAN log sequence not found.

From: Maxim Demenko <mdemenko_at_gmail.com>
Date: Sat, 13 Aug 2005 18:54:45 +0200
Message-ID: <ddl8je$n5s$01$1@news.t-online.com>

Joel Garry schrieb:

> kechup wrote:
> 

>>Hello,
>>
>>We switched to RMAN managed backups. Prior to this we deleted
>>archivelogs by means of OS. Now I made database backup, and then
>>archivelog backup. I tested if I can restore archivelog from backup and
>>I have got thes message:
>>RMAN-00571: ===========================================================
>>RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
>>RMAN-00571: ===========================================================
>>RMAN-03002: failure of restore command at 08/12/2005 11:09:33
>>RMAN-06026: some targets not found - aborting restore
>>RMAN-06025: no backup of log thread 1 seq 33 scn 37770144 found to
>>restore
>>RMAN-06025: no backup of log thread 1 seq 32 scn 37770142 found to
>>restore
>>RMAN-06025: no backup of log thread 1 seq 31 scn 37763529 found to
>>restore
>>RMAN-06025: no backup of log thread 1 seq 30 scn 37763527 found to
>>restore
>>RMAN-06025: no backup of log thread 1 seq 29 scn 37763522 found to
>>restore
>>RMAN-06025: no backup of log thread 1 seq 28 scn 37763446 found to
>>restore
>>
>>All the reported log sequences were deleted before the RMAN`s database
>>backup and are not needed for database recovery. I tried crosscheck and
>>then DELETE EXPIRED but without success.
>>
>>So now I have database backup, all archivelogs in backup needed for
>>recovery but can`t restore them because were deleted by means of OS and
>>they are not needed for reco.

> 
> 
> See Case 2 in
> http://metalink.oracle.com/metalink/plsql/ml2_documents.showFrameDocument?p_database_id=NOT&p_id=155656.1
>  

I think, that case doesn't apply, although , the OP is not very clear about the steps which were done

>>Any idea?

> 
> 
> Well, obviously they were needed.  Remember, RMAN backup is
> inconsistent, the controlfile is snapshotted when RMAN starts.  So,
> those transactions in progress (which might be other than user
> transactions) will need to be recovered to make the database
> consistent, the logs in question may be from before RMAN starting the
> backup.
> 
> I'll slightly disagree with Sybrand - it's ok, even desireable to keep
> older arcs around and then delete with OS commands - BUT, you have to
> keep enough of them, certainly more than one backup cycle.
> 
> OW!  My hands!  oww!  OWWW!
> 
> jg
> --
> @home.com is bogus.
> "Financial Engineering Group"  huh-huh
> http://www.signonsandiego.com/uniontrib/20050812/news_1b12shelter.html
> 

I may be wrong, but in my understanding that can not happen ( if you are doing the usual RMAN backup ). By backup RMAN issue a checkpoint for every datafile being backed up and write the appropiated SCN into image copies / backup sets. By recovery you need the logs that contain the redo from the lowest SCN written to fileheaders of backupsets/image copies . Older are not needed. The only situation i can imagine - the controlfile was restored from backup and it had lower SCN that backup begin, in that case redos should be applied which were done before the backup started, but , as i said, it is only guess - the OP didn't provide all the details.

Another point is , all these considerations - which logs are needed , which not - are an additional point of failure (IMO Sybrand is correct ), the best is to implement a reasonable retention policy and after that don't care about archived logs - RMAN keeps track of what is really needed alone.

Best regards

Maxim Received on Sat Aug 13 2005 - 11:54:45 CDT