Physical standby database fail-over

Question

Hi,
I am working on Oracle 10.2.0.3 on Solaris SPARC 64-bit.
I have a Dataguard configuration with a single Physical standby database that uses real time application. We had a major application upgrade yesterday and before the start of upgrade, we cancelled the media recovery and disabled the log_archive_dest_n so that it doesn't ship the archive logs to standby site. We left the dataguard configuration in this mode incase of a rollback.
Primary:
alter system set log_archive_dest_state_2='DEFER';
alter system switch logfile;
Standby:
alter database recover managed standby database cancel;Due to application upgrade induced problems we had to failover to the physical standby, which was not in sync with primary from yesterday. I used the following method to fail-over since i do not want to apply any redo from yesterday.
Standby:
alter database activate physical standby database;
alter database open;
shutdown immediate;
startupSo, after this step, the database was a stand alone database, which doesn't have any standby databases yet (but it still has log_archive_config parameter set and log_archive_dest_n parameters set but i have 'DEFER' the log_archive_dest_n pointing to the old primary). I have even changed the "archive log deletion policy to NONE"
RMAN> configure archivelog deletion policy to none;After the fail-over was completed, the log sequence started from Sequence 1. We cleared the FRA to make space for the new archive logs and started off a FULL database backup (backup incremental level 0 database plus archivelog delete input). The backup succeded but we got these alerts in the backup log that RMAN cannot delete the archivelogs.
RMAN-08137: WARNING: archive log not deleted as it is still neededMy question here is
1) Even though i have disabled the log_archive_dest_n parameters, why is RMAN not able to delete the archivelogs after backup when there is no standby database for this failed-over database?
2) Are all the old backups marked unusable after a fail-over is performed?
FYI... flashback database was not used in this case as it did not server our purpose.
Any information or documentation links would be greatly appreciated.
Thanks,
Harris.

Answer 1

Thanks for the reply.
The FINISH FORCE works in some cases but if there is an archive gap (though it didn't report in our case), it might not work some times (DOCID: 846087.1). So, we followed the Switch-over & Fail-Over best practices where it mentioned about this "ACTIVE PHYSICAL STANDBY" for a fail-over if you intend not to apply any archivelogs. The process we followed is the Right one.
Anyhow, we got the issue resolved. Below is the resolution path.
1) Even though if you DEFER the LOG_ARCHIVE_DEST_STATE_N parameter's on the primary, there are some situations where the Primary database in a dataguard configuration where it will not delete the archive logs due to some SCN issues. This issue may or may not arise in all fail-over scenarios. If it does, then do the following checks
Follow DOCID: 803635.1, which talks about a PLSQL procedure to check for problematic SCN's in a dataguard configuration even though the physical standby databases are no available (i.e., if the dataguard parameters are set, log_archive_config, log_archive_dest_n='SERVICE=..." still set and even though corresponding LOG_ARCHIVE_DEST_STATE_N parameters are DEFERRED).
If this procedure returns any rows, then the primary database is not able to delete the archivelogs because it is still thinking there is a standby database and trying to save the archive logs because of the SCN conflict.
So, the best thing to do is, remove the DG related parameters from the spfile (log_archive_config, log_archive_dest_n parameters).
After i made these changes, i ran a test backup using "backup archivelog all delete input", the archive logs got deleted after backup without any issues.
Thanks,
Harris.
Edited by: user11971589 on Nov 18, 2010 2:55 PM