DB Recovery - the steps taken
Date: 25 Jan 95 08:01:48 +1000
Message-ID: <1995Jan25.080148.1_at_cbr.hhcs.gov.au>
I just finished helping one of our interstate DBAs recovery the Production database that they accidentally deleted and was interested in any comments on the steps we took.
(We are running 7.0.13 on VMS 5.5-2 but should be similar for any platform)
- Backed up the existing control file (only thing left of the DB)
- Located latest successful full database backup and restored it to the original DB disks.
- Located all ARCHIVED REDO log files and restored them to a separate disk.
- Copied the latest control file in to replace the ones just restored from tape.
- Mounted the database EXCLUSIVE.
- Did a RECOVER DATABASE UNTIL CANCEL; and replied AUTO when prompted with the first SUGGESTED archive file to reapply. Actually, we tried just hitting RETURN and using the suggested file but it only did the one file and then told us it needed a specific REDO LOG sequence and the current REDO LOG was not that number. Anyway the AUTO seems to have worked its way through the archived REDO LOG files ok.
- When the recover step failed to find log file xxxx69 (logs were only up to xxxx68 anyway) we cancelled out. All archived REDO LOGS had been successfully applied.
- We tried an ALTER DATABASE OPEN NORESETLOGS; but it said the SYSTEM tablespace still needed media recovery.
- Remembering that even the REDO LOG files had been lost and restored to an older version we then did an ALTER DATABASE OPEN RESETLOGS;
- Once the database came up, we shut it down and did a new backup so we could recover forward from this point once we were operational again.
- At this moment the database is up and we are awaiting the arrival of some users to check if any transactions have been lost.
My only reservation about the above steps is the RESTLOGS which means that when the database was shutdown (before being deleted accidentally) were there committed transactions in the REDO logs that had not been written to the archives.
Archives are only written when the REDO LOG file fills so we had a potential of 10Meg of un-archived transactions sitting in one of the REDO LOG files that got deleted.
Given that we lost the REDO LOG files too there was no other way to OPEN the database except to RESETLOGS.
Is there anything else I could/should have done?
-- Bruce... pihlab_at_cbr.hhcs.gov.au *******************************************************************Received on Tue Jan 24 1995 - 23:01:48 CET
* Bruce Pihlamae -- Database Administration *
* Commonwealth Department of Human Services and Health *
* Canberra, ACT, Australia (W) 06-289-7056 *
*=================================================================*
* These are my own thoughts and opinions, few that I have. *
******************************************************************* "The more complex the argument gets, the easier it is to refute." "Killing is wrong!" -- Trent 'The Uncatchable' Castanaveras