On Fri, 2010-06-04 at 16:03 +0100, Robert Milkowski
wrote:> On 04/06/2010 15:46, James Carlson wrote:
> > Petr Benes wrote:
> >
> >> add to /etc/system something like (value depends on your needs)
> >>
> >> * limit greedy ZFS to 4 GiB
> >> set zfs:zfs_arc_max = 4294967296
> >>
> >> And yes, this has nothing to do with zones :-).
> >>
> > That leaves unanswered the underlying question: why do you need to do
> > this at all? Isn''t the ZFS ARC supposed to release memory
when the
> > system is under pressure? Is that mechanism not working well in some
> > cases ... ?
> >
> >
>
> My understanding is that if kmem gets heavily fragmaneted ZFS
won''t be
> able to give back much memory.
>
The slab allocator and virtual memory are designed to prevent memory
fragmentation. That said, it is possible that certain devices which
need physically contiguous memory may be affected by physical address
fragmentation. I''m not sure exactly what kind of fragmentation
you''re
talking about here though...
- Garrett