Date: Wed, 4 Aug 2010 23:19:59 -0700 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: "Alex V. Petrov" <alexvpetrov@gmail.com> Cc: freebsd-stable@freebsd.org Subject: Re: zpool - low speed write Message-ID: <20100805061959.GA92106@icarus.home.lan> In-Reply-To: <201008051409.57751.alexvpetrov@gmail.com> References: <201008042008.25679.alexvpetrov@gmail.com> <201008051247.43260.alexvpetrov@gmail.com> <20100805053504.GA91196@icarus.home.lan> <201008051409.57751.alexvpetrov@gmail.com>
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On Thu, Aug 05, 2010 at 02:09:57PM +0800, Alex V. Petrov wrote: > В сообщении от 5 августа 2010 13:35:04 вы написали: > > Write performance here is abysmal, agreed. This is very odd. > > > > I hate to say this, but can you remove ahci.ko (ahci_load="yes") from > > your loader.conf and reboot? You may need to change filesystem names > > around in /etc/fstab for your OS disk (assuming it's on ada0), but for > > ZFS it should just magically find the disks on adXX. > > > > If you could also provide pciconf -lvc output that would be helpful. > > Thanks. > > dd if=/dev/zero of=/tank/test.zero bs=3M count=1000 > 1000+0 records in > 1000+0 records out > 3145728000 bytes transferred in 485.431690 secs (6480269 bytes/sec) Can you please remove use of the zpool entirely (e.g. zpool destroy tank) and do a write test to each disk itself? E.g.: dd if=/dev/zero of=/dev/ad8 bs=64k count=1000000 dd if=/dev/zero of=/dev/ad10 bs=64k count=1000000 dd if=/dev/zero of=/dev/ad12 bs=64k count=1000000 I don't recommend using large block sizes (e.g. bs=1M, bs=3M). If all of the above dds show good/decent throughput, then there's something strange going on with ZFS. If this is the case, I would recommend filing a PR and posting to freebsd-fs about the problem, pointing folks to this thread. If all of the dds show bad throughput, then could you please do the following: - Provide vmstat -i output - Install ports/sysutils/smartmontools and run smartctl -a /dev/ad8, smartctl -a /dev/ad10, and smartctl -a /dev/ad12 If only one of the dds shows bad throughput, then please: - Install ports/sysutils/smartmontools and run smartctl -a /dev/XXX, where XXX is the disk which has bad throughput - Try making a ZFS pool with all 3 disks, but then do "zpool offline tank XXX" and then re-attempt the following dd: dd if=/dev/zero of=/tank/test.zero bs=64k count=1000000 And see what throughput looks like. Thanks. -- | 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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