RE: I/O tuning... Allocating spindles to databases

From: Kevin Closson <kevinc_at_polyserve.com>
Date: Thu, 15 Sep 2005 14:44:56 -0700
Message-ID: <B9782AD410794F4687F2B5B4A6FF3501021D4B21@ex1.ms.polyserve.com>

 >>>Even if such access patterns are less than likely, it's

>>>still important to know how storage responds in worst case
>>>scenarios. Cache on the SAN/NAS is not a bad thing. I
>>>can't think of a situation where it would *degrade*
>>>performance merely by its presence.

I've done a lot of benchmarking on systems configured with over 1000 disk drives and believe me, caching data that will never be revisted does not boost performance.

Think FTS. I have used arrays that allow you to completely disable cache and doing so on the tables that sustain scans was often a performance boost. Mileage varies.

>>>We've had a NetApp with rather fast disk and huge cache.
>>>Burst performance indeed can be good. But, the thing has
>>>effectively single gigabit fiber backbone and a single and
>>>heavily burdened storage processor that renders it incapable
>>>of sustaining more than maybe sixty (60) megabytes/sec

That is because it is a single headed NAS. You need to see HP's story with the Enterprise File Server Clustered Gateway. Supports 16 active:active heads with no SPOF.

ftp://ftp.compaq.com/pub/products/storageworks/efs/4AA0-0283ENW.pdf

Besides, it's OEMed PolyServe :-)

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Received on Thu Sep 15 2005 - 16:46:58 CDT