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

[Eric Sandeen <sandeen@xxxxxxxxxxx>]

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...

I don't know if the storage you're on passes barriers or not, but xfs
has barriers on by default, while ext3 does not.  ext3 will still likely
win the "untar a kernel" race, but for a fairer test, make the barrier
settings consistent between the two.

-Eric