Date: Wed, 14 Jan 2004 15:11:30 +0200 From: Ari Suutari <ari@suutari.iki.fi> To: Raymond Wiker <Raymond.Wiker@fast.no>, freebsd-stable@freebsd.org Subject: Re: Adaptect raid performance with FreeBSD Message-ID: <200401141511.30958.ari@suutari.iki.fi> In-Reply-To: <16389.15817.322098.577889@raw.grenland.fast.no> References: <200401141453.50150.ari@suutari.iki.fi> <16389.15817.322098.577889@raw.grenland.fast.no>
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On Wednesday 14 January 2004 15:02, Raymond Wiker wrote: > Ari Suutari writes: > > dd if=/dev/rda1s1a of=/dev/null bs=1m count=100 > > 100+0 records in > > 100+0 records out > > 104857600 bytes transferred in 4.193832 secs (25002814 bytes/sec) > > > > So, I get only about 25MB/s. Shouldn't I be getting something > > like 70 MB/s, or even more since there are two disks that > > can server read requests ? > > Have you tried other block sizes? I think you may be able to > get better results by going to a lower block size (e.g, 64k instead of > 1m). Some experimentation will show which block size(s) work best. I tried with 32k, 64k, 256k and 512k. Speed is about the same with every block size. Block sizes less than 32k seem to give even worse performance. Ari S. -- Ari Suutari Lemi, Finland
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