On Wed, Sep 09, 2009 at 07:41:08PM +1000, Danny Carroll wrote: > On 9/09/2009 6:33 PM, Pawel Jakub Dawidek wrote: > >On Wed, Sep 09, 2009 at 09:07:15AM +0200, Gerrit Kühn wrote: > > > >>On Tue, 8 Sep 2009 18:44:13 +0200 Pawel Jakub Dawidek<p...@freebsd.org> > >>wrote about Re: zfs kernel panic: > >> > >>PJD> If this is amd64, add vm.kmem_size="4G" to your loader.conf back. > >> > >>What about vm.kmem_size_max? Does that also need tuning? > >> > >No, this should be auto-tuned to some very large value. > > > > > Pawel (et al), > > Would it be possible for you to post to the list your ideas of a > complete set of tuning parameters for ZFS on amd64? I have used the > wiki article as a reference (http://wiki.freebsd.org/ZFSTuningGuide) but > it states that if you have > 2g ram and 7.2 then you do not need to tune > at all.
I think that was the idea, although I see no reason to have less kernel
address space than physical memory (except there might be other
in-kernel variables auto-tuned based on kmem size).
> I for one would be interested in learning a little more about how the
> memory should be tuned. Specifically what might be interesting is to
> know, once a parameter is set, is there an easy way to find out how it's
> being used? i.e. If you start limiting the arc, is is possible to know
> what sort of hit/miss rate you are getting.
There are ARC statistics available here:
# sysctl kstat.zfs
--
Pawel Jakub Dawidek http://www.wheel.pl
p...@freebsd.org http://www.FreeBSD.org
FreeBSD committer Am I Evil? Yes, I Am!
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