Date: Mon, 2 May 2005 14:48:33 +0200 (CEST) From: kama <kama@pvp.se> To: Eric Anderson <anderson@centtech.com> Cc: =?ISO-8859-15?Q?=22Arne_=5C=22W=F6rner=5C=22=22?= <arne_woerner@yahoo.com> Subject: Re: Very low disk performance on 5.x Message-ID: <20050502144658.H22614@ns1.as.pvp.se> In-Reply-To: <42761FA7.1030500@centtech.com> References: <20050501112351.4184.qmail@web41205.mail.yahoo.com> <42761FA7.1030500@centtech.com>
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On Mon, 2 May 2005, Eric Anderson wrote: > I'll be honest here, I don't care much if the speed difference between > 4.X and 5.X is measureable, or whatever. What I find is a little > telling of an issue somewhere, is that READS are slower than WRITES! > This is totally bogus to me - dd'ing a file to a filesystem, then > umounting should take longer than dd'ing from the disk to /dev/null, it > nearly every config I can dream up. Maybe it's the speed at which > /dev/null can gobble bits (seems highly unlikely!), or maybe GEOM is > busy doing a check or some routine to data being accessed directly from > the disk device instead of through a filesystem? I don't know, but it > is an issue, and I'm sure we'll get nailed up to a fence in some > benchmark somewhere if we don't fix it.. dev-null is not the issue... my own written testprogram that only read up data to a buffer in memory showed the same results as doing a dd to dev-null. /Bjorn
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