From: Dave Chinner <david@fromorbit.com>
To: Hans-Peter Jansen <hpj@urpla.net>
Cc: xfs@oss.sgi.com
Subject: Re: xfs write performance issue
Date: Fri, 20 Mar 2015 10:18:54 +1100 [thread overview]
Message-ID: <20150319231854.GL10105@dastard> (raw)
In-Reply-To: <8976870.8vOdNBKrI1@xrated>
On Thu, Mar 19, 2015 at 06:01:50PM +0100, Hans-Peter Jansen wrote:
> ~# LANG=C xfs_info /dev/sdc1
> meta-data=/dev/sdc1 isize=256 agcount=17, agsize=183105406
> blks
> = sectsz=512 attr=2, projid32bit=0
> = crc=0 finobt=0
> data = bsize=4096 blocks=2929687287, imaxpct=5
> = sunit=0 swidth=0 blks
> naming =version 2 bsize=4096 ascii-ci=0 ftype=0
> log =Intern bsize=4096 blocks=32768, version=2
> = sectsz=512 sunit=0 blks, lazy-count=1
> realtime =none extsz=4096 blocks=0, rtextents=0
....
> ~# LANG=C dd if=Django_Unchained.mp4 of=/dev/null bs=1M
> 1305+1 records in
> 1305+1 records out
> 1369162196 bytes (1.4 GB) copied, 3.32714 s, 412 MB/s
>
> Write performance is disastrous: it's about 1.5 MB/s.
>
> ~# LANG=C dd if=Django_Unchained.mp4 of=xxx bs=1M
> 482+0 records in
> 482+0 records out
> 505413632 bytes (505 MB) copied, 368.816 s, 1.4 MB/s
Why did it stop half way through? ENOSPC?
> 1083+0 records in
> 1083+0 records out
> 1135607808 bytes (1.1 GB) copied, 840.072 s, 1.4 MB/s
That's incomplete, too.
> The question is, what could explain these numbers. Bad alignment? Bad stripe
> size? And what can I do to resolve this - without loosing all my data..
More than likely you've fragmented free space, and so writes
are small random write IO. Output of 'df -h' and:
$ xfs_db -r -c "freesp -s" <dev>
would be instructive.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2015-03-19 23:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-19 17:01 xfs write performance issue Hans-Peter Jansen
2015-03-19 17:10 ` Emmanuel Florac
2015-03-19 23:18 ` Dave Chinner [this message]
2015-03-20 8:05 ` Hans-Peter Jansen
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