Re: Extreme slowness with xfs [WAS: Re: Slowness with new pc]

[Justin Piszcz <jpiszcz@lucidpixels.com>]

On Sun, 23 Nov 2008, Stian Jordet wrote:

> ti., 18.11.2008 kl. 11.51 -0200, skrev Sergio Luis:
>> please post your config and dmesg output. It might help people try to
>> identify something wrong.
>
> (see http://marc.info/?l=linux-kernel&m=122676220019858&w=2 for the
> start of this thread)
>
> Hmm. I have now converted my root and /home filesystems to ext3, and
> that actually fixed it (!). I have no idea why xfs is performing so
> extremely poorly on this machine, i'm running xfs on every filesystem on
> eight other computers (one heavy loaded server, as well).
>
> Anyway, I'm now unpacking the 2.6.27.6 kernel in 15 seconds, with xfs on
> the same array it used between five and six minutes.
>
> I still have a xfs array, and when I copy files to or from that array,
> the gnome session practically freezes, and the load average easily goes
> beyond 10.
>
> How should I debug this? I'm not very eager about reformatting my 1,5TB
> xfs array... Besides, xfs have never let me down earlier.
>
> Thanks.
>
> Please cc me on any replies.
>
> Regards,
> Stian
>
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As the original posted stated:

1. please post dmesg output
2. you may want to include your kernel .config
3. xfs_info /dev/mdX or /dev/device may also be useful
4. you can also check fragmentation:
    # xfs_db -c frag -f /dev/md2
    actual 257492, ideal 242687, fragmentation factor 5.75%
5. something sounds very strange, I also run XFS on a lot of systems and
    have never heard of that before..
6. also post your /etc/fstab options
7. what distribution are you running?
8. are -only- the two fujitsu's (raid0) affected or are other arrays
    affected on this HW as well (separate disks etc)?
9. you can also compile in support for latency_top & power_top to see
    if there is any excessive polling going on by any one specific
    device/function as well

Justin.