zfs arc - just take it all and be good to me

[Jeremy Chadwick]

On Wed, Aug 11, 2010 at 07:43:24AM +0200, Matthias Gamsjager wrote:
> > Please, insert into /boot/loader.conf only this options:
> > vm.kmem_size="999M"
> > vm.kmem_size_max="999M"
> > vfs.zfs.arc_max="160M"
> > vfs.zfs.prefetch_disable=1
> >
> > And after reboot, please run dd...
> 
> vfs.zfs.arc_max="160M" should be enough to limit the size of the arc.

That depends on exactly what date/time your kernel sources are, and what
tag/release you're running.  The ARC limiting feature was changed at one
point in time (from a "high watermark" to a hard-set limit).

The OP didn't include uname -a output, so we don't know what exact
version of the kernel/system he's running.

> and I'm not sure if that  ( vm.kmem_size="999M"
> ,vm.kmem_size_max="999M") is such a good idea.

Yes, it is a good idea.

And you shouldn't need to adjust vm.kmem_size_max, only vm.kmem_size.

-- 
| Jeremy Chadwick                                   jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |