From: Nathan Scott <nathans@aconex.com>
To: Michael Monnerie <michael.monnerie@is.it-management.at>
Cc: xfs@oss.sgi.com
Subject: Re: 4K drives, sectsz=512, bsize=4096
Date: Wed, 1 Sep 2010 08:34:28 +1000 (EST) [thread overview]
Message-ID: <1177874643.527261283294068615.JavaMail.root@mail-au.aconex.com> (raw)
In-Reply-To: <201009010007.23899@zmi.at>
----- "Michael Monnerie" <michael.monnerie@is.it-management.at> wrote:
> On Dienstag, 31. August 2010 Eric Sandeen wrote:
> > If you do it right (and especially vs. if you do it wrong) it
> > should be a bit faster if all IOs are 4k aligned on the disk.
>
> And that's what's interesting me: why? Won't XFS do all I/Os at
> minimum
> for a given block size? Or is it possible XFS does write only a single
> sector? I'd expect the smallest I/O size to be the block size, but it
> seems I'm wrong?
Log I/O and direct writes are sector sized & aligned.
> I guess there's no way to "convert" an existing XFS with
> sectsz=512,bsize=4096 to sectsz=4096,bsize=4096? Maybe that's only a
> flag that can be changed?
There's no way (other than dump, mkfs & restore), the filesystem is laid
out differently (most data structures, like superblocks and other metadata
become 4K aligned).
cheers.
--
Nathan
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next prev parent reply other threads:[~2010-08-31 22:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-30 7:56 4K drives, sectsz=512, bsize=4096 Michael Monnerie
2010-08-31 21:01 ` Michael Monnerie
2010-08-31 21:16 ` Eric Sandeen
2010-08-31 22:07 ` Michael Monnerie
2010-08-31 22:15 ` Eric Sandeen
2010-08-31 23:12 ` Michael Monnerie
2010-08-31 22:34 ` Nathan Scott [this message]
2010-09-01 5:35 ` Gim Leong Chin
2010-09-01 5:59 ` Nathan Scott
2010-09-01 7:38 ` Michael Monnerie
2010-09-01 10:13 ` Christoph Hellwig
2010-09-01 10:24 ` Christoph Hellwig
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