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Perc 3 DC

From: Glyn Astill <glynastill(at)yahoo(dot)co(dot)uk>
To: pgsql-performance(at)postgresql(dot)org
Subject: Perc 3 DC
Date: 2008-11-22 14:18:25
Message-ID: 680067.16755.qm@web23608.mail.ird.yahoo.com (view raw or flat)
Thread:
Lists: pgsql-performance
Hi chaps,

I've had this old card sitting on my desk for a while. It appears to be a U160 card with 128Mb BBU so I thought I'd wang it in my test machine (denian etch) and give it a bash.

I set up 4 36Gb drives in raid 0+1, but I don't seem to be able to get more than 20MB/s write speed out of it for large files (2XRAM usual tests with dd from dev/zero). I don't expect anything great, but I thought it'd do a little better than that.

I've tried writeback and write through modes, tried changing cache flush times, disabled and enabled multiple PCI delayed transactions, all seem to have little effect.

Finally I decided to wave goodbye to Dell's firmware. LSI has it down as a MegaRAID 493 elite 1600, so I flashed it with their latest firmware.  Doesn't seem to have helped either though.

Has anybody else used this card in the past?  I'm wondering if this is a driver issue, or if the card is and always was just crap? If so I'll proabably try sw raid on it instead.

Any thoughts?

Glyn


      

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