Date: Sun, 28 Mar 2010 11:06:29 +0400 From: Alexey Tarasov <me@lexasoft.ru> To: freebsd-fs@freebsd.org Subject: ZFS raidz and 4k sector disks Message-ID: <DEB8C86C-A672-4E61-B42F-630C26164DED@lexasoft.ru>
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Hello.
I have reviewed a lot of discussion about new WD 4k sector disks =
(...EARS).
I have RAIDZ pool of such disks with very bad performance. Now my GPT =
ZFS partitions don't start from value dividable by 4 (162).
Some guys noticed that aligning ZFS partitions according to =
recommendation wouldn't help at all because RAIDZ uses variable stripe =
size.
So where is the bottleneck of this configuration: 1) in ZFS which =
doesn't know about 4k sectorsize? 2) maybe somewhere inside FreeBSD VFS =
code or disk driver code? 3) somewhere else?
If you doesn't want to use ZFS there are two ways to deal with this =
problem:
1) Use GNOP with virtual 4k sectorsize.
2) Use UFS on properly aligned partition and some tuning.
--
Alexey Tarasov
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