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RE: Datafiles on SAN?

From: Jesse, Rich <>
Date: Tue, 15 Jul 2003 11:08:26 -0500
Message-Id: <>



Not yet.

We're VERY I/O bound on our 6-way HP K570 and an AutoRAID (see "BAARF") for our ERP system running a hybrid (OLTP/reporting) DB. We've tested an IBM FastT900, a smallish box in the SAN world, with wonderful preliminary results for us. I'm sure that the perf tuners here on the list have already predicted what we've seen. While our I/O bandwidth went up, that caused the CPUs to spin more to generate all those I/O requests. And while our tests showed a marked improvement in total response time, individual wait events are still high in some cases. I take this to possibly be evidence that if we were able to redesign our apps (purchased and homegrown) to reduce total I/O, maybe we wouldn't need new hardware.

So what's the bottom line of this incoherent babble? We're going SAN. Our I/Os went from 400-500 peak on the AutoRAID to 22000 peak (cached) with 5000 sustained (uncached) on the SAN, with a mitigated 2GB cache (1GB mirrored, flushed). Hopefully, we'll be able to also upgrade the DB server next year to compensate for the inevitable CPU bottleneck. And while this is going on, we're attempting to change our design methods to better allow for scalability. Not that it'll help our purchased apps, though...

One more note: because of time constraints, we were not able to test the SAN with anything close to our production DB/app K570 server (test box was a dual 2.4Ghz Windohs PC that was a pain to setup). The purpose of the test was to see what kind of raw and buffered I/O we could get from the FastT900 and a copy of our 30GB production DB. We will hopefully be testing the SAN on a K-box soon to see exactly what kind of CPU it's going to take to feed the I/O.

HTH! GL! Rich

Rich Jesse                           System/Database Administrator                  Quad/Tech Inc, Sussex, WI USA

> -----Original Message-----
> From: Tim Levatich []
> Sent: Tuesday, July 15, 2003 11:29 AM
> To: Multiple recipients of list ORACLE-L
> Subject: Datafiles on SAN?
> Is anyone putting datafiles on SAN storage?
> Success? Horror? Tell me a story.
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Received on Tue Jul 15 2003 - 11:08:26 CDT

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