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From: Brian Candler <B.Candler@pobox.com>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: xfs@oss.sgi.com
Subject: Re: df bigger than ls?
Date: Thu, 8 Mar 2012 09:59:32 +0000	[thread overview]
Message-ID: <20120308095932.GA24187@nsrc.org> (raw)
In-Reply-To: <20120308085035.GA23992@nsrc.org>

On Thu, Mar 08, 2012 at 08:50:35AM +0000, Brian Candler wrote:
> Aha.  This may well be what is screwing up gluster's disk usage on a striped
> volume - I believe XFS is preallocating space which is actually going to end
> up being a hole!

Here is a standalone testcase.

$ for i in {0..19}; do dd if=/dev/zero of=testfile bs=128k count=1 seek=$[$i * 12]; done
$ xfs_bmap testfile
testfile:
	0: [0..255]: 1465133392..1465133647
	1: [256..3071]: hole
	2: [3072..5119]: 1465136464..1465138511
	3: [5120..6143]: hole
	4: [6144..10239]: 1465139536..1465143631
	5: [10240..12287]: hole
	6: [12288..20479]: 1465145680..1465153871
	7: [20480..21503]: hole
	8: [21504..37887]: 1465154896..1465171279
	9: [37888..39935]: hole
	10: [39936..58623]: 1465173328..1465192015

I expected to see: 20 extents of 256 blocks and 19 holes of 2816 blocks.

Regards,

Brian.

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  reply	other threads:[~2012-03-08  9:59 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-07 15:54 df bigger than ls? Brian Candler
2012-03-07 17:16 ` Brian Candler
2012-03-07 18:04   ` Eric Sandeen
2012-03-08  2:10     ` Dave Chinner
2012-03-08  2:17       ` Eric Sandeen
2012-03-08  9:10         ` Brian Candler
2012-03-08  9:28           ` Dave Chinner
2012-03-08 16:23       ` Ben Myers
2012-03-09  0:17         ` Dave Chinner
2012-03-09  1:56           ` Ben Myers
2012-03-09  2:57             ` Dave Chinner
2012-03-08  8:04     ` Arkadiusz Miśkiewicz
2012-03-08 10:03       ` Dave Chinner
2012-03-08  8:50     ` Brian Candler
2012-03-08  9:59       ` Brian Candler [this message]
2012-03-08 10:22         ` Dave Chinner

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