Performance difference between UFS and ZFS with NFS

[Rick Romero]

Quoting Eric Browning <ericbrowning at skaggscatholiccenter.org>:


> Right now I'm going to have to abandon ZFS until it works with NFS.  I
> don't want to get into a finger pointing game, I'd just like to help get
> this fixed, I have one old i386 server I can try things out on if that
> helps and it's already on 9 stable and ZFS v28.

When you created the raid0, did you leave the disk cache enabled?  I  
know it's against the purpose of ZFS to leave the controller and drive  
caches enabled, but it sure improves performance.

In both our cases, (IIRC)NFS will also wait for that commit response -  
so if the caches are disabled, NFS really begins to drag. I believe  
there was a commit in 9.2 that allowed modification of a sysctl to  
disable/change the NFS commit... in some manner.. I forget exactly..  
they all tie in together.

Also disable the cache flushing.
See https://wiki.freebsd.org/ZFSTuningGuide
And http://forums.freebsd.org/archive/index.php/t-30856.html


Rick