Date: Fri, 25 Jul 2008 11:18:41 +0200 From: Kris Kennaway <kris@FreeBSD.org> To: Claus Guttesen <kometen@gmail.com> Cc: FreeBSD Stable <freebsd-stable@freebsd.org> Subject: Re: zfs, raidz, spare and jbod Message-ID: <48899A71.4040508@FreeBSD.org> In-Reply-To: <b41c75520807250046y4ba061a2i63d3a40b7fc76170@mail.gmail.com> References: <b41c75520807250046y4ba061a2i63d3a40b7fc76170@mail.gmail.com>
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Claus Guttesen wrote: > Hi. > > I installed FreeBSD 7 a few days ago and upgraded to the latest stable > release using GENERIC kernel. I also added these entries to > /boot/loader.conf: > > vm.kmem_size="1536M" > vm.kmem_size_max="1536M" > vfs.zfs.prefetch_disable=1 > > Initially prefetch was enabled and I would experience hangs but after > disabling prefetch copying large amounts of data would go along > without problems. To see if FreeBSD 8 (current) had better (copy) > performance I upgraded to current as of yesterday. After upgrading and > rebooting the server responded fine. > > The server is a supermicro with a quad-core harpertown e5405 with two > internal sata-drives and 8 GB of ram. I installed an areca arc-1680 > sas-controller and configured it in jbod-mode. I attached an external > sas-cabinet with 16 sas-disks at 1 TB (931 binary GB). > > I created a raidz2 pool with 10 disks and added one spare. I copied > approx. 1 TB of small files (each approx. 1 MB) and during the copy I > simulated a disk-crash by pulling one of the disks out of the cabinet. > Zfs did not activate the spare and the copying stopped until I > rebooted after 5-10 minutes. When I performed a 'zpool status' the > command would not complete. I did not see any messages in > /var/log/message. State in top showed 'ufs-'. That means that it was UFS that hung, not ZFS. What was the process backtrace, and what role does UFS play on this system? Kris > A similar test on solaris express developer edition b79 activated the > spare after zfs tried to write to the missing disk enough times and > then marked it as faulted. Has any one else tried to simulate a > disk-crash in raidz(2) and succeeded? >
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