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Date: Sun, 4 Apr 2010 23:18:45 +0400
From: Mikle <nekoexmachina@gmail.com>
To: freebsd-fs@freebsd.org
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Subject: Strange ZFS performance
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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?

Wbr,