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Date: Wed, 4 Jun 2008 01:28:59 -0400
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: Questions for article
Message-ID: <20080604052859.GA6509@infradead.org>
References: <13033.143.166.226.57.1212526129.squirrel@tomslinux.homelinux.org> <4845C254.6050104@sandeen.net>
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To: Eric Sandeen <sandeen@sandeen.net>
Cc: Thomas King <kingttx@tomslinux.homelinux.org>, xfs@oss.sgi.com

On Tue, Jun 03, 2008 at 05:14:44PM -0500, Eric Sandeen wrote:
> It's also not clear to me that this is really a critical feature for
> large filesystems; space allocation is not done block by block per se in
> xfs, as Mr. Newman seems (?) to imply (?)  The block granularity is
> there throughout the fs but I'm not sure how much it matters in
> practice.  Dave...?

For streaming I/O workloads it doesn't matter anymore, see Dave's 2006
OLS talk.  The direct to bio I/O path mitigates any blocksize impact.