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

[Stian Jordet]

ti., 25.11.2008 kl. 01.09 +0100, skrev Sven-Haegar Koch:
> I had the same problem when I tried it on my laptop (T60) - using it on 
> the unencrypted root filesystem (with /usr/src) took ages, using it on 
> the LUKS encrypted /home was blasing fast - on the same disk.
> 
> This test was some time ago with something like 2.6.20 or 2.6.24 - I 
> gave up and reformatted / with ext3 as I needed the machine.
> 
> I think barriers were the problem, they seem to cost performance like 
> hell, especially for operations with many small files. My laptop used 
> barriers for xfs on the direct partition, but not on crypto drivermapper 
> mounts.
> 
> So perhaps try mounting with nobarrier and see if the speed problem goes 
> away - but know that you sacrifice some crash-resilience when doing so.

Barriers were the problem indeed. My old system had no problems with
barriers, but here it did an incredible difference.

Thanks!
-Stian

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