From: Dave Chinner <david@fromorbit.com>
To: Spelic <spelic@shiftmail.org>
Cc: xfs@oss.sgi.com
Subject: Re: Questions on RAID alignment
Date: Fri, 21 Sep 2012 08:38:52 +1000 [thread overview]
Message-ID: <20120920223852.GI31501@dastard> (raw)
In-Reply-To: <505AF9EA.7030603@shiftmail.org>
On Thu, Sep 20, 2012 at 01:11:38PM +0200, Spelic wrote:
> Hello list
> a few questions
>
> 1- Does XFS support alignment to concatenation RAIDs (e.g. linear
> over raid1) similarly to striped ones?
No. It's being considered and I know how to do it, but it's lower
priority than other stuff I'm working on at the moment.
> I am guessing probably su and
> sw should not be specified and the agcount should be multiple of the
> number of the concatenated devices, is that correct?
If you are concatenating RAID0/5/6, then you shoul duse su/sw as per
the alignment of the volumes being concatenated.
> 2- Can mkfs parameters be altered after creation, e.g. after growing
> a RAID and then growing the XFS fs, can I also alter su, sw, agcount
> somehow?
You can alter su/sw as a mount option if the filesystem was made
with them initially.
> 3- I seem to remember there was an xattr that one could attach to
> /home (if /home was under XFS) so that every user (subdir of /home)
> would get a different AG in a different RAID device. I cannot find
> that information anymore on the internet; could you refresh my mind?
Nothing of the sort. if you are using the inode64 allocator, then
each new directory is placed i a different AG. That's as good as it
gets right now.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2012-09-20 22:37 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-20 11:11 Questions on RAID alignment Spelic
2012-09-20 12:05 ` Emmanuel Florac
2012-09-20 22:38 ` Dave Chinner [this message]
2012-09-20 23:11 ` Stan Hoeppner
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