Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 08 Mar 2008 00:53:58 -0800
From:      Reed Wilson <cedilla@gmail.com>
To:        freebsd-fs@freebsd.org
Subject:   ZFS zvol write speed incredibly slow
Message-ID:  <47D25426.8050505@gmail.com>

next in thread | raw e-mail | index | archive | help
Hi guys!

I just got 7.0-RELEASE installed and running on my home server, and I've 
noticed incredibly slow write speeds to a ZFS zvol. Reading speeds seem 
normal. It may be related to the OpenSolaris bug #6428639:
http://bugs.opensolaris.org/view_bug.do?bug_id=6428639

 >> To another zpool:
# dd if=junk of=/tank2/junk bs=65536
1024+0 records in
1024+0 records out
67108864 bytes transferred in 0.331802 secs (202255676 bytes/sec)

 >> To a zvol in the same pool:
dd if=junk of=/dev/zvol/tank/tempvol bs=65536
1024+0 records in
1024+0 records out
67108864 bytes transferred in 11.575167 secs (5797658 bytes/sec)

Using smaller block sizes exacerbates the problem (444606 bytes/sec with 
4096-byte blocks!)

-- Reed



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?47D25426.8050505>