zfs, raidz, spare and jbod
kometen at gmail.com
Fri Jul 25 09:24:50 UTC 2008
>> I installed FreeBSD 7 a few days ago and upgraded to the latest stable
>> release using GENERIC kernel. I also added these entries to
>> 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?
Arghh.. Typo, I meant 'zfs-'. Pardon.
My boot-disk is plain ufs2 but the disk I pulled out was in the raidz2-pool.
When lenity and cruelty play for a kingdom,
the gentlest gamester is the soonest winner.
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