Oracle7 - Recovery after loss of redo log group

From: Kim Johnson <kim_at_medicus.com>
Date: Thu, 14 Oct 1993 00:15:06 GMT
Message-ID: <1993Oct14.001506.23247_at_medicus.com>


I'm attempting to simulate error situations to test my recovery procedures. My database is running in archivelog mode with automatic archiving enabled, and contains two groups of online redo logs, each with two members (ie, mirrored online redo logs).

I'm having a problem testing the "loss of entire log group" situation. Oracle documentation (_Oracle7 Server Administrator's Guide_) discusses various recovery procedures depending on whether the redo log group is current, inactive, archived, etc.

When the lost group is active and already archived, the documentation states that you can "restore the group from the archived copy, renaming it to the restored location, and restart the database". When I tried this I got error ORA-00327 "physical size less than needed".

When the lost group is current, the documentation states that you should perform "cancel-based, time-based, or changed-based recovery", and "rename the damaged online redo log group to a new location. (You do not need to create the files.)". When I try to rename the files, I get error ORA-01512 "new file not found".

If I try to restore all files from a backup and do incomplete media recovery with "restore database until cancel using backup controlfile", applying redo logs up to the last archive taken, I end up with message ORA-01195 "online backup of file needs more recovery to be consistent" when doing "alter database open resetlogs" command.

Although the likelihood of losing a log group (the members will be on different disks) may be somewhat remote in production, I still need some way to bring the database back up, which I cannot do right now.

Any ideas?



Kim Johnson
kim_at_medicus.com
Software Engineer
Medicus Systems Corp.
Alameda, CA Received on Thu Oct 14 1993 - 01:15:06 CET

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