Date: Tue, 01 Apr 2003 09:19:50 -0500 From: Jason Andresen <jandrese@mitre.org> To: Craig Boston <craig@meoqu.gank.org> Cc: FreeBSD Stable List <freebsd-stable@freebsd.org> Subject: Re: vinum performance Message-ID: <3E89A006.7020301@mitre.org> In-Reply-To: <1049147744.98637.57.camel@owen1492.uf.corelab.com> References: <20030330125138.K23911@leelou.in.tern> <3E870CC7.5000204@mac.com> <20030330175605.E23911@leelou.in.tern> <3E87204C.5060304@ludd.luth.se> <3E88524A.1060600@mitre.org> <3E88AECD.10607@liwing.de> <3E88B601.90802@mitre.org> <1049147744.98637.57.camel@owen1492.uf.corelab.com>
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Craig Boston wrote: > On Mon, 2003-03-31 at 15:41, Jason Andresen wrote: > >>(Both of these were on previously untouched files to prevent any >>caching, and the "write" test is on a new file, not rewriting an old one) >>Write speed: >>81920000 bytes transferred in 3.761307 secs (21779663 bytes/sec) >>Read speed: >>81920000 bytes transferred in 3.488978 secs (23479655 bytes/sec) >> >>But on the RAID5: >>Write speed: >>81920000 bytes transferred in 17.651300 secs (4641018 bytes/sec) >>Read speed: >>81920000 bytes transferred in 4.304083 secs (19033090 bytes/sec) > > > Disclaimer: IANAVE (I am not a Vinum Expert) > > What block size are you using with dd? If your bs= is less than your > RAID stripe size, it seems like it would end up doing unnecessary > read-modify-write cycles... Commands used: dd if=/dev/zero of=test bs=8192 count=1000 and dd if=random_unused_file_larger_than_80MB of=/dev/null bs=8192 \ count=10000 My stripe size is 384k. -- \ |_ _|__ __|_ \ __| Jason Andresen jandrese@mitre.org |\/ | | | / _| Network and Distributed Systems Engineer _| _|___| _| _|_\___| Office: 703-883-7755
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