Date: Sun, 6 Oct 2002 11:30:16 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: Vallo Kallaste <kalts@estpak.ee> Cc: "Greg 'groggy' Lehey" <grog@FreeBSD.ORG>, Lars Eggert <larse@ISI.EDU>, Poul-Henning Kamp <phk@critter.freebsd.dk>, n0go013 <ttz@blahdeblah.demon.co.uk>, current <freebsd-current@FreeBSD.ORG> Subject: Re: [ GEOM tests ] vinum drives lost Message-ID: <200210061830.g96IUGNF043142@apollo.backplane.com> References: <62515.1033758160@critter.freebsd.dk> <3D9DEFF7.7050508@isi.edu> <20021005125505.GA1248@tiiu.internal> <20021005221456.GR83766@wantadilla.lemis.com> <20021006072155.GA1117@tiiu.internal>
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Yes, ccd is fairly light weight. 'man tuning' and 'man ccd' has
a lot of information on how to use it. I generally recommend
using a stripe size of 1152 for multitasking loads. Only use a
small/tiny stripe size if you need single-tasking sequential
performance (and even then you can take tune the stripe to the drive's
own caching capability).
The biggest mistake most people make when using striping is that
they use too small a stripe size which causes nearly every read() or
write() to have to be split across multiple drives, which multiplies
the overhead, or causes sequential reads of medium sized files to
constantly seek multiple drives, destroying the effectiveness of having
two seekable heads in the first place.
-Matt
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