RE: archivelog performance issues
Date: Tue, 7 Jul 2009 12:31:43 -0400
I agree with Joseph.
Additionally, in my mind, the decision as to whether you run in archivelog mode should really be about recoverability and uptime needs. Noarchivelog implies cold backups. You must take a down time to do the backup. Noarchivelog means you can only recover up to the point in time of the last good cold backup. With archivelog mode, you can do hot backups and recoverability is to the point in time of the last committed transaction. There's lots more flexibility that archivelog mode offer you, as well. Those are just the two most important points.
Seems to me, you should make the decision as to whether archivelog mode is a requirement, and then, if needed, make changes to support your required performance with it enabled.
In my opinion, for *almost all* production databases, archivelog mode is a foregone conclusion. In my opinion, there are very few production databases that can really be adequately served with noarchivelog mode.
In conclusion, as Joseph mentioned, for the size of the database you have and the transaction volume you're talking about, switching archivelog mode on shouldn't even noticeable at all.
Some things to check before you switch to archive log mode:
- How frequently are you seeing log switches, at peak load time? Size your online redo so that you get a switch about every 15-30 minutes, at peak.
- If your load variaes greatly from peak to non-peak, you may want to use archive_lag_target to get more frequent switches during off-peak times.
- Make sure you have at least three redo log groups.
Hope that helps,
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Joey D'Antoni
Sent: Tuesday, July 07, 2009 12:09 PM
To: jachang_at_lanl.gov; oracle-l_at_freelists.org Subject: Re: archivelog performance issues
How is your storage arranged? In general, with a database of that size, I can't imagine a significant performance impact from running in archivelog mode, unless the storage was horribly misconfigured.
From: Julio Aguilar-Chang <jachang_at_lanl.gov> To: Oracle-L Freelists <oracle-l_at_freelists.org> Sent: Tuesday, July 7, 2009 12:06:33 PM
Subject: archivelog performance issues
What are the performance issues I should be aware of if I decide to enable archivelog mode on an OLTP database? I just inherited this database (about 40GB in size, ~200 users, ~2000 transactions per day), it is not in archivelog mode, and the manager who owns it (not well versed in Oracle) tells me that the previous DBA who just left did not enable archiving for database performance reasons. The Oracle server is an HP DL385, dual core, with 16GB of memory. Is there a good reason based on performance for not enabling archivelog mode?
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http://www.freelists.org/webpage/oracle-l Received on Tue Jul 07 2009 - 11:31:43 CDT