Re: suddenly slow writes on XFS Filesystem

Martin Steigerwald
2012-05-06T21:43:27Z

Am Sonntag, 6. Mai 2012 schrieb Stan Hoeppner:
> On 5/6/2012 5:33 AM, Martin Steigerwald wrote:
> > Am Sonntag, 6. Mai 2012 schrieb Stefan Priebe:
> >> It is a raid 10 of 20 SATA Disks and i can only write to them with
> >> about 700kb/s while doing random i/o. I tried vanilla Kernel 3.0.30
> >> and 3.3.4 - no difference. Writing to another partition on another
> >> xfs array works fine.
> >
> > Additionally what RAID is this? SoftRAID or some - which one? -
> > hardware RAID controller? And what disks are used, whats the rpm of
> > these?
>
> I doubt much of this stuff matters. Stefan's filesystem is 96% full,
> w/~200GB free. This free space is likely heavily fragmented. If he's
> doing allocation in this fragmented free space I'd think that would
> fully explain his write performance dropping off a cliff due to massive
> head seeking.

Hmmm, I thought about that low free space percentage, too, but then 200 GB
free still sounded like quite much to me. Nonetheless, since according to
Stefan freeing some space solved the slowness issue, that seems to have
been it.

Can free space be defragmented in XFS? xfs_fsr only tries to defragment
files as far as I know.

Thanks,
--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
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