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From: Eric Sandeen <sandeen@sandeen.net>
To: Janos Haar <janos.haar@netcenter.hu>
Cc: linux-xfs@oss.sgi.com
Subject: Re: 2 question about XFS fragmentation and _fsr: SPLITTED Q1:sparse files
Date: Wed, 27 Apr 2011 15:18:33 -0500	[thread overview]
Message-ID: <4DB87A19.30306@sandeen.net> (raw)
In-Reply-To: <45DD2814B0C84BF3AFD76721A0178E50@myXP>

On 4/26/11 4:51 PM, Janos Haar wrote:

<snip>

>>> In the result, actually we have >6TB images on the 3TB disk, wich is
>>> 97.9% fragmented.
>>
>> How are you determining that figure?
> 
> [root@UNISTORE admin]# cat xfs_get_frat_ratio
> echo loop0
> xfs_db -c frag -r /dev/loop0
> [root@UNISTORE admin]# ./xfs_get_frat_ratio
> loop0
> actual 7650952, ideal 752501, fragmentation factor 90.16%

so you had 7650952 extents on the fs, ideally you'd have 752501, or so xfs_db says...

Another way of looking at this is that you have about 10 extents per file on average.

Depending on the size of the files, this may be perfectly fine.
Is, for example, a 10G file in ten 1G extents really a problem?

I doubt that fragmentation is your performance problem here.

-Eric

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  reply	other threads:[~2011-04-27 20:15 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-11 17:39 2 question about XFS fragmentation and _fsr Janos Haar
2011-04-11 20:37 ` Stan Hoeppner
2011-04-26 21:21   ` 2 question about XFS fragmentation and _fsr: SPLITTED Q2:normal files, samba share Janos Haar
2011-04-26 21:50   ` 2 question about XFS fragmentation and _fsr: SPLITTED Q1:sparese files Janos Haar
2011-04-11 21:42 ` 2 question about XFS fragmentation and _fsr Dave Chinner
2011-04-11 23:37   ` Christoph Hellwig
2011-04-26 21:49     ` 2 question about XFS fragmentation and _fsr: Q2 Janos Haar
2011-04-26 21:51   ` 2 question about XFS fragmentation and _fsr: SPLITTED Q1:sparse files Janos Haar
2011-04-27 20:18     ` Eric Sandeen [this message]
2011-04-27 20:37       ` Eric Sandeen
2011-04-26 21:51   ` 2 question about XFS fragmentation and _fsr: SPLITTED Q2:normal files, samba share Janos Haar

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