Re: Online Redo Log During a Hot Backup

Hi

This is precisely why you must have the database in archivelog mode in order to place tablespaces in backup mode.

When a redo log fills up, it now gets archived thereby guaranteeing Oracle has the necessary redo logs required for recoverability. In the 3 hours it takes to fully backup the database, you'll now have approximately the 12 archived redo logs which may be required to recover these datafiles to the point of time the backup completed. You'll of course continue to archive the redo logs so you can use the backups to recover to the current (or any) point of time. Note you may have somewhat more than 12 logs as redo activity will increase for those tablespaces currently in backup mode (unless you use RMAN). You may want to consider having more online redo log groups to minimize the likelihood of redo logs not being archived/checkpointed at the time it needs to be overwritten.

Cheers

Richard

• Original Message ----- From: "aamgm service" <aamgms_at_aamines.co.zw> To: <oracle-l_at_freelists.org> Sent: Wednesday, September 22, 2004 8:41 PM Subject: Online Redo Log During a Hot Backup

Dear Gurus,

I have been running my database in noarchive mode and I want to switch to Archivelog mode. I am running Oracle 7.3.4. I have three groups of redo logs that are 20MB each.
My question is what happens to filled online redo logs during a hot/online backup?? My fear is my database could hang when all redo logs fill up before my backup completes because it usually takes 2-3 hours (backup) to complete? and my log switches occur in 15-20 mins.

TIA
Regards

---

Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.742 / Virus Database: 495 - Release Date: 2004-08-19

--

http://www.freelists.org/webpage/oracle-l

--

http://www.freelists.org/webpage/oracle-l Received on Wed Sep 22 2004 - 07:48:17 CDT