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

[Justin Piszcz]

On Tue, 25 Nov 2008, Stian Jordet wrote:

> ma., 24.11.2008 kl. 04.50 -0500, skrev Justin Piszcz:
>> While there still may be something else wrong, the first problem I see is
>> your sunit and swidth are set to 0.
>>
>> Please read, a good article on what they are and how to set them:
>> http://www.socalsysadmin.com/
>
> Oh, this was new to me. But the setting didn't change anything. I can
> copy one large file between the xfs and ext3 disk (both ways), and I get
> speeds between 160 and 200 MB/s. But unpacking the kernel source takes
> between 5 and 10 minutes on the xfs disk, and a mere 15 seconds on the
> ext3... (and it also used to take between 5 and 10 minutes when I had
> xfs on the raid0, so it doesn't seem to be hardware related...)
>
> If anyone has anything more I can try before I do the lengthy process of
> backup 1TB, reformat and restore...
>
> Thanks :)
>
> Regards,
> Stian
>

When you 'unpack the kernel source' ext3 will cache it etc, best way to 
test:

/usr/bin/time cmd
or
time cmd

where cmd is: bash -c 'tar xvf file.tar; sync'

Make sure its a tar and not gzip/bzip2 (limited by CPU/etc)

The other option is the relatime you stated, use this instead:

defaults,noatime,logbufs=8,logbsize=262144

then tell me what you get
(instead of relatime)

Justin.