Date: Thu, 5 Aug 2004 09:25:22 +0200 From: Stijn Hoop <stijn@win.tue.nl> To: "H. Sandring" <h.sandring@gmx.net> Cc: freebsd-questions@freebsd.org Subject: Re: RAID 5 stripe size Message-ID: <20040805072521.GH43462@pcwin002.win.tue.nl> In-Reply-To: <003601c47aba$2dd9ca10$0501a8c0@kojo> References: <003601c47aba$2dd9ca10$0501a8c0@kojo>
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[-- Attachment #1 --] Hi, On Thu, Aug 05, 2004 at 03:02:25PM +0800, H. Sandring wrote: > Is there an intelligent way of choosing the stripe size of a RAID 5 > array? From man vinum: "For optimum performance, stripes should be at least 128 kB in size: anything smaller will result in a significant increase in I/O activ- ity due to mapping of individual requests over multiple disks. The performance improvement due to the increased number of concurrent transfers caused by this mapping will not make up for the performance drop due to the increase in latency. A good guideline for stripe size is between 256 kB and 512 kB. Avoid powers of 2, however: they tend to cause all superblocks to be placed on the first subdisk." I expect this to be true for non-vinum RAID-5 volumes as well. HTH, --Stijn -- The most reliable proof that there are extraterrestrial intelligent lifeforms out there is that nobody actually tries to get in contact with us. -- Dirk Mueller [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFBEeDhY3r/tLQmfWcRAonLAJ0R814R3HFIy7blSw6puUSEO4OEQwCdFLMC l5z28RNS0aIC6DecCpRf2DA= =s4GF -----END PGP SIGNATURE-----
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