Re: Strange delete performance using XFS

[Thomas Kaehn <tk@westend.com>]

Hi Justin,

On Wed, Apr 04, 2007 at 09:29:46AM -0400, Justin Piszcz wrote:
> >Please see below for "time" output.
> >
> >| # time for i in `seq 1 100000`; do dd if=/dev/zero of=$i bs=1k count=20 
> >>/dev/null 2>&1; done
> >|
> >| real    6m6.814s
> >| user    0m30.290s
> >| sys     2m42.562s
> >| # time rm -rf y
> >|
> >| real    5m18.034s
> >| user    0m0.036s
> >| sys     0m8.169s

> Deletes on XFS is one area that is a little slower than other filesystems. 
> You can increase the log size during the creation of the filesystem and 
> also increase logbufs to 8 and that might help.

Thanks for your suggestions.

I also tried to increase the log size and logbufs mount option. This
optimizes create and delete times to the above values (with default options
both are around 9-10 minutes).

The strange thing is that on a similar Dell machines using XFS, too,
deletes take only ten seconds which would match user and system time.

More than five minutes for deleting 100000 files where ext3 needs
3 seconds on the same machine is actually more than a little bit slower
- to my mind there must be something wrong. JFS needs around 18 seconds.

However I am not sure if the problem is hardware or software related.
I've also tried to use the newest 3ware firmware - but this did not lead
to an improvement.

Ciao,
Thomas
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