ZFS performance

[Kris Kennaway]

On Tue, May 29, 2007 at 10:28:05PM +0200, St?le Kristoffersen wrote:
> On 2007-05-29 at 14:54, Kris Kennaway wrote:
> > On Tue, May 29, 2007 at 01:12:18AM +0200, St?le Kristoffersen wrote:
> > > On 2007-05-14 at 10:42, Nick Gustas wrote:
> > > > I see the same behavior that St?le is seeing, I can "fix" it by setting 
> > > > vfs.zfs.prefetch_disable="1" in loader.conf.  I'm assuming something in 
> > > > the prefetch code isn't quite right?
> > > 
> > > Ah, this _greatly_ improved the usability of my fileserver! Thanks for the
> > > tip :)
> > 
> > How does filesystem performance change?  I thought ZFS needs to do
> > prefetching to improve read performance.
> 
> How the performance changed was dramatically, it went from beeing about
> useless for doing anything other than watching one stream from it, to
> tackle several concurrent streams without problems. I whish prefetching
> would work correctly, it should improve performance even more.

Well, that is one aspect of performance, but prefetching is presumably
important for other workloads.

Kris