Re: 4K drives, sectsz=512, bsize=4096

Gim Leong Chin
2010-09-01T05:34:34Z

Hi,

I would like to know how the inode size should be configured for 4 kB sector drives?

Should we leave it at the default 256 bytes, or set it to the maximum of 2 kB?

Do inodes occupy discrete sectors, or do they occupy part of the filesystem block?

GL

--- On Wed, 1/9/10, Nathan Scott <nathans@aconex.com> wrote:

> From: Nathan Scott <nathans@aconex.com>
> Subject: Re: 4K drives, sectsz=512, bsize=4096
> To: "Michael Monnerie" <michael.monnerie@is.it-management.at>
> Cc: xfs@oss.sgi.com
> Date: Wednesday, 1 September, 2010, 6:34 AM
>
> ----- "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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