Re: managing REDO-LOG correctly

Tischendorf und Schuch wrote:

> Ingersheim, 16.06.97
>
> Dear Oracle Experts,
>
> We are supporting Oracle 7.1 running on a NT 3.51 PC in archive
> log mode. This means, that a lot of archive log files are written.
> We have a cold backup each day using the Oracle Backup Manager.
> But the backup is done by not so well skilled persons. How can we
> manage the redo log files? When can we delete them best and how?
> Is there a chance to delete them immediate after finishing the
> backup successful. How can we control whether the backup has been
> completed correct.
> Do you have any idea?

Well, if you are performing a *full cold backup* each day you don't need the redo logs *once the backup has successfully completed*. The only case you might want them was if you wanted to do a restore of your database to some point in time between full cold backups, which is unlikely, but still...

As regards when to get rid of the redo logs, well I tend to keep a few days worth online even though we too do full cold backups each day. It will help speed up database recovery if that's ever needed, as you don't need to restore the archive logs from tape. It will also help you if you latest cold backup tape is bad, as you can go back to a prior one without having to dig out the older logs as well. As regards to how best to do it, we just have a post backup script that deletes the old log files automatically.

One other point to mention is make sure you mirror your redo log and control files across different disks.

As regards testing your backup:

1. Make sure you have a tape system (hardware) that auto-verifies the tape contents as they are written. If not, make sure you set-up your backup software to perform a verify pass once the backup is completed. And *always* check your backup logs first thing every morning.
2. Perform regular restores from your tapes to a test area - or better still a test machine - to make sure the backups work. We perform restores to our development machine and test that the database starts up and runs OK.

Steve Phelan. Received on Tue Jun 17 1997 - 00:00:00 CDT