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From: Dave Chinner <david@fromorbit.com>
To: Danny Shavit <danny@zadarastorage.com>
Cc: Eric Sandeen <sandeen@sandeen.net>, xfs-oss <xfs@oss.sgi.com>
Subject: Re: xfs metadata overhead
Date: Sat, 25 Jun 2016 08:51:45 +1000	[thread overview]
Message-ID: <20160624225145.GF12670@dastard> (raw)
In-Reply-To: <CAC=x_0g_iktOKOKiRF5Ku7N-PSbCXOR+Amhm577YjNYQaRPjeA@mail.gmail.com>

On Fri, Jun 24, 2016 at 04:21:39PM +0300, Danny Shavit wrote:
> I see.
> So using bulk_stat ioctl in similar way to xfs_fsr and summing allocated
> size will result with  more accurate number?

No. du includes *directory blocks* in it's sum. bulkstat only counts
inodes, which is not counted by du and is part of the metadata you
have already accounted for. Even then, bulkstat doesn't give an
accurate account o space used by inodes because they can be sparsely
allocated from within inode chunks.

Just snapshot the volume, run metadump on the snapshot - it's the
fastest, most reliable way to work out how much metadata is in a
filesystem right now...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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      reply	other threads:[~2016-06-24 22:51 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-22 15:58 xfs metadata overhead Danny Shavit
2016-06-22 22:51 ` Dave Chinner
2016-06-23 15:04   ` Danny Shavit
2016-06-23 18:12     ` Eric Sandeen
     [not found]       ` <CAC=x_0hnGQHAenv985+FusWxK_63AatB_XK_mqbAmyt=OxqYrg@mail.gmail.com>
2016-06-24 13:17         ` Eric Sandeen
2016-06-24 13:21           ` Danny Shavit
2016-06-24 22:51             ` Dave Chinner [this message]

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