ZFS committed to the FreeBSD base.

Bernd Walter ticso at cicely12.cicely.de
Sat Apr 7 21:24:29 UTC 2007

On Sat, Apr 07, 2007 at 09:15:17PM +0200, Pawel Jakub Dawidek wrote:
> On Sat, Apr 07, 2007 at 08:03:19PM +0200, Bernd Walter wrote:
> > Now with 240M kmem it looks good, but I'm still unshure:
> > kstat.zfs.misc.arcstats.c_min: 67108864
> > kstat.zfs.misc.arcstats.c_max: 188743680
> > kstat.zfs.misc.arcstats.size: 87653376
> > c_max seemed to be increasing with kmem, but I did compare it with a
> > remebered value.
> > Should be good with:
> > vm.kmem_size: 251658240
> > But top shows wired memory which is roughly twice the size of
> > arcstats.size, so I'm still worried about kmem exhaustion if ARC runs
> > up to c_max.
> > Since the c_min/c_max values also influence the available RAM for other
> > purposes as well, can we have it at least a loader.conf tuneable?
> Just committed a change. You can tune max and min ARC size via
> vfs.zfs.arc_max and vfs.zfs.arc_min tunnables.

Thanks - I'd set c_max to 80M now and will see what happens, since
I had such a panic again with 240M kmem.

I'm a bit confused about the calculation as such.
Lets asume a 4G i386 system.
arg_c = 512M
c_min = 512M
c_max = 3G
But isn't this KVA space, of which we usually can't have 3G on i386
without limiting userland to 1G?
Even 512M KVA sounds very much on a i386, since 4G systems usually
have more use for limited KVA.

B.Walter                http://www.bwct.de      http://www.fizon.de
bernd at bwct.de           info at bwct.de            support at fizon.de

More information about the freebsd-current mailing list