Date: Sun, 4 Apr 2010 13:41:27 -0700 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: Mikle <nekoexmachina@gmail.com> Cc: freebsd-fs@freebsd.org Subject: Re: Strange ZFS performance Message-ID: <20100404204127.GA53469@icarus.home.lan> In-Reply-To: <20100404191844.GA5071@takino.homeftp.org> References: <20100404191844.GA5071@takino.homeftp.org>
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On Sun, Apr 04, 2010 at 11:18:45PM +0400, Mikle wrote: > Hello, list! > I've got some strange problem with one-disk zfs-pool: read/write performance for the files on the fs (dd if=/dev/zero of=/mountpoint/file bs=4M count=100) gives me only 2 MB/s, while reading from the disk (dd if=/dev/disk of=/dev/zero bs=4M count=100) gives me ~70MB/s. > pool is about 80% full; PC with the pool has 2GB of ram (1.5 of which is free); i've done no tuning in loader.conf and sysctl.conf for zfs. In dmesg there is no error-messages related to the disk (dmesg|grep ^ad12); s.m.a.r.t. seems OK. > Some time ago disk was OK, nothing in software/hardware has changed from that day. > Any ideas what could have happen to the disk? Please provide the following output: 1) uname -a 2) sysctl kstat.zfs.misc.arcstats 3) smartctl -a /dev/ad12 Also, does rebooting the box restore write speed (yes, this is a serious question/recommendation)? -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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