ZFS kmem_map too small.

Niki Denev nike_d at cytexbg.com
Mon Nov 5 15:31:57 PST 2007

On Nov 5, 2007 11:50 PM, Andrew Thompson <thompsa at freebsd.org> wrote:
> On Mon, Oct 08, 2007 at 02:15:23PM +0200, Pawel Jakub Dawidek wrote:
> > Here are some updates:
> >
> > I was able to reproduce the panic by rsyncing big files and trying
> > bonnie++ test suggested in this thread.
> >
> > Can you guys retry with this patch:
> >
> >       http://people.freebsd.org/~pjd/patches/vm_kern.c.2.patch
> >
> > It's a hack, yes, but allows to mitigate the problem quite well. I'm
> > looking for a solution that can be used for 7.0 before we find a better
> > fix.
> Do you still plan to commit this for 7.0 or is a better solution in the
> works? I would assume something would need to be in before RC1.
> > BTW. To use ZFS you _must_ increase vm.kmem_size/vm.kmem_size_max.
> > If you have the problem discussed here and you're using standard values,
> > please retry with vm.kmem_size/vm.kmem_size_max set to at least 600MB in
> > /boot/loader.conf.
> >
> > I'm not sure if it's not too late to ask re@ about increasing the
> > default kmem size at least on amd64. ~300MB we have there is silly
> > small.
> >

I have fairly easy reproductable (bonnie++) kmem_map too small panics
on AMD64 even with kmem_size and kmem_size_max to 1G on 8Gig machine.
I've tried setting them to 2G but the kernel panics on boot.
I have compiled in debugger support and can provide backtraces and
testing if needed (the machine is still not in production).

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