Date: Fri, 30 May 2003 11:22:16 -0400 From: Chuck Swiger <cswiger@mac.com> To: peo@intersonic.se Cc: freebsd-questions@freebsd.org Subject: Re: Vinum performance Message-ID: <3ED77728.8080009@mac.com> In-Reply-To: <3ED74FF4.2010905@intersonic.se> References: <3ED72156.1070905@intersonic.se> <20030530101845.GG40976@wantadilla.lemis.com> <3ED74FF4.2010905@intersonic.se>
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Per olof Ljungmark wrote: [ ... ] > The bottleneck is write performance, reading from the documentation this > is normally a weak point in Vinum/raid5 setups. It's not vinum; RAID-5 write performance is going to be relatively slow even with hardware parity/XOR support. > The volume will be used for storing temporary files with sizes in the > 1-4MB range, a few hundreds at a time. Reads are fine but writes a bit > slow. What ratio of reads to writes do you expect? > Copying 170 files total 319MB TO the Vinum volume takes about 2m45s. > Copying same files FROM the Vinum volume to another volume on a hardware > raid5 controller takes 43s. A 3-1 ratio in speeds for software RAID-5 versus hardware doesn't strike me as being very wrong.... > This machine is not in production yet so I can still make changes to the > configuration. The current block size is 16384 and the stripe size 419k. > I assume it would be a good idea to change that to for example 491,520? ...or try a few stripe sizes, such as 64K or 128K. -Chuck
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