The Oracle (tm) Users' Co-Operative FAQ

How Do I Recover From Loss of a Inactive Redo Log Group?


Author's name: Allan W. Tham

Author's Email: allanwtham@hotmail.com

Date written: Feb 28 2002

Oracle version(s): 8.1.7.0.0

You suspected you lost the only copy of redo group. You did a check on v$logfile and found that there is an invalid status for a redo log group. You further checked that this group is inactive and archived is yes from v$log.

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Work for Archive Log Mode ON

1. To investigate what status is the missing redo log is -
    a. select * from v$logfile shows which group is INVALID
    b. select * from v$log shows the status of the invalid group
2. Now that you are confirmed that the lost redo file is an INACTIVE redo log, shutdown the database - shutdown immediate
3. Mount the database - Startup mount
4. Since the redo log group is inactive and is archived, just clear the redo log -
    alter database clear logfile group N (where N is the group # of the lost redo log)
5. Open the database - Alter database open
6. Check status - select * from v$log shows a new redo with UNUSED status
7. Do a full backup if you want
8. Done

(Note: Being the easiest case to recover, inactive and archived redo logs recovery is quite straightforward. The difficulty level will be
    1. Lost of current redo
    2. Lost of active redo
    3. Lost of unarchived redo
    4. Lost of inactive redo
See Oracle9i User-Managed Backup and Recovery Guide for inactive and unarchived lost of redo log
Remember, it's always a good idea to multiplex the redo log groups)

 


Further reading:Metalink note 1060608.6, 1044466.6, Oracle9i User-Managed Backup and Recovery Guide


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