Re: Serious WAPL performance problems

[Stephan <stephanwib%googlemail.com@localhost>]

2012/10/25 Edgar Fuß <ef%math.uni-bonn.de@localhost>:
> Now this is getting weird. I have retried the experiment with neither softdep
> nor log, i.e. with a plain old FFS, and that performs as well as or even
> outperforms WAPL.
> With both a 5.1_STABLE and a 6.0_RELEASE kernel, on a 16k fsbsize FFSv2, the
> svn updates takes around 5 seconds with either log or without.
> On the 8k fsbsize FFSv1, it takes 7 seconds with WAPL and 5 without!
> So there seems to be something seriously wrong with WAPL if can degrade fs
> performance, isn't it?


I always found FFS being slow when creating or deleting many files.
For example, on 6.0 with FFSv2 and WAPBL it took 20 sec. to complete
this:


time seq 1 30000 | xargs touch


The experimental ZFS port finishes the same task in 0,2 sec.