FreeBSD 8.1-Prerelease Panic amd64 w/ZFS..

Jeremy Chadwick freebsd at
Fri May 28 13:59:10 UTC 2010

On Fri, May 28, 2010 at 12:13:51PM +0300, Andriy Gapon wrote:
> on 28/05/2010 10:30 Howard Leadmon said the following:
> >  I know there used to be some issues with this a while back, but thought
> > with the 8.x FBSD servers most of this tuned itself, or then again maybe
> > this is something different.
> > 
> >  
> > 
> >  For the first time I ever recall, I found my FreeBSD 8 server was crashed
> > this past morning, with the following error:
> > 
> >  
> > 
> > panic:kmem_malloc(131072):kmem_map to small: 1296826368 total allocated
> > 
> > cupid=4
> O wow, this is an amd64 system (with 4G RAM) and you've got "kmem_map too
> small".  That's very very strange.

It is?  On amd64, vm.kmem_size (not vm.kmem_size_max) is what has to be
increased.  I can point folks to the "official" statement from pjd@ and
some others if need be.  For a very long time I questioned this because
for an even longer amount of time we were being told to increase

vm.kmem_size_max, by default, is already huge on amd64 (~320GB or
something like that).  Proof:

vm.kmem_size_max: 329853485875

To the OP: you will need to increase vm.kmem_size in /boot/loader.conf
and reboot the system.  "What value do I pick?"  With 4GB, I would
recommend you use these two variables:


This will increase the available kmem, and also limit the ARC size
explicitly to nothing larger than 1.5GB.  This should stabilise your

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

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