Subject: Re: Low AAC performance but only when tested through the file system
To: Olaf Seibert <>
From: Bill Studenmund <>
List: current-users
Date: 11/28/2003 19:25:05
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On Thu, Nov 27, 2003 at 06:02:52PM +0100, Olaf Seibert wrote:
> I am still struggling with the performance of an Adaptec 2120S RAID
> controller (aac0). When testing with bonnie++ (from pkgsrc), write
> performance is only around 4M/sec. The number of xfers/second, as shown
> by `systat vmstat', is only around 60 while it is writing and only
> around 100 when reading. This is surprisingly low.
> However, when I test with a benchmark called RawIO (see
> on the (unused) raw swap partition,
> I get much better results. Sequential writing is around 35M/sec, and the
> number of xfers/sec is over 1000, peaking at some 1900.
> So it's not like the card is not capable of proper transfer counts and
> speeds, it seems it is held back somehow by the file system or buffer
> cache.

What is the setup of your raid volume?

Take care,


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