Re: RMAN backup slows database performance to a crawl

From: Kevin Lidh <>
Date: Fri, 11 Jul 2008 09:20:50 -0600
Message-Id: <>

I'm going to preface this with pointing out that I'm not a SAN expert (a fact that will be obvious in a moment). But we had an issue with the company I support where our file systems for datafiles and the file systems for the backups shared write cache. This wasn't cache you could partition due to the age of the technology. So when we had a heavy backup running on one server, performance would suffer on a completely different server. This made troubleshooting very difficult. The problem was that the only option you had was to "opt in" or "opt out" of cache. If we didn't use it, the backups were too slow. If we did use it, the customer was impacted. We found an older Clarion and moved our backups to it. Even though the technology was even older, the write cache was completely separate and both the backups and database performance improved.

On Fri, 2008-07-11 at 10:32 -0400, Finn Jorgensen wrote:
> No. Completely different IO subsystems.
> Finn
> On Fri, Jul 11, 2008 at 9:50 AM, Dba DBA <> wrote:
> > are you writing your RMAN backups to the same set of disks that you are
> > reading from ? make sure your backups are on different sets of disks. if
> > your on a SAN, ask your administrator to map you out a mount point that maps
> > through the same to a different raid group preferably on a different HBA.
> > alot of SAN guys don't want to put in the effort. Its really just a GUI and
> > will not take alot of time.
> --

Received on Fri Jul 11 2008 - 10:20:50 CDT

Original text of this message