Date: Sat, 30 Jul 2005 12:17:20 -0700 From: Julian Elischer <julian@elischer.org> To: Poul-Henning Kamp <phk@haven.freebsd.dk> Cc: FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: Apparent strange disk behaviour in 6.0 Message-ID: <42EBD240.9090208@elischer.org> In-Reply-To: <98853.1122719635@phk.freebsd.dk> References: <98853.1122719635@phk.freebsd.dk>
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Poul-Henning Kamp wrote: > In message <42EB5687.2070400@elischer.org>, Julian Elischer writes: > >>Poul-Henning Kamp wrote: >> >>>In message <42E88135.30603@elischer.org>, Julian Elischer writes: >>> >>>Please use gstat and look at the service times instead of the >>>busy percentage. >> >>The snapshot below is typical when doing tar from one drive to another.. >>(tar c -C /disk1 f- .|tar x -C /disk2 -f - ) >> >>dT: 1.052 flag_I 1000000us sizeof 240 i -1 >> L(q) ops/s r/s kBps ms/r w/s kBps ms/w d/s kBps ms/d %busy Name >> 0 405 405 1057 0.2 0 0 0.0 0 0 0.0 9.8 | ad0 >> 0 405 405 1057 0.3 0 0 0.0 0 0 0.0 11.0 | ad0s2 >> 0 866 3 46 0.4 863 8459 0.7 0 0 0.0 63.8 | da0 >> 25 866 3 46 0.5 863 8459 0.8 0 0 0.0 66.1 | da0s1 >> 0 405 405 1057 0.3 0 0 0.0 0 0 0.0 12.1 | ad0s2f >> 195 866 3 46 0.5 863 8459 0.8 0 0 0.0 68.1 | da0s1d >> >>even though the process should be disk limitted neither of the disks is anywhere >>near 100%. > > > This looks like an awful lot of small files since you write 8 times as much data > as you read ? > > Since the write service time (ms/w) is low, I pressume you have > some hefty disk hardware (with cache ?) > > Presumably you're using softupdates ? > > I wouldn't be surprised if you were limited by system time rather than disk in > this scenario ? system is 87% idle >
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