Critical mmap failure?

[Konrad Heuer]

On Wed, 7 Apr 2004, Andrew MacIntyre wrote:

> On Tue, 6 Apr 2004, Konrad Heuer wrote:
>
> > * The machines in question are all DELL PowerEdge 2650, three with
> >   RAID controllers, one without. The main difference in hardware is
> >   that the system on wich the error occurs has 4 GB of memory, the
> >   others 2 GB. There are no significant differences in the kernel
> >   configuration files except driver entries for RAID or not.
>
> I think you are running into issues associated with the kernel autosizing
> various data structures and running low on VM address space.
>
> If you can, try reducing the problematic machine to 2GB of memory and see
> whether the problems persist.  If they don't, then it is this issue and
> you're going to have to fiddle with the kernel config.
>
> I've seen posts in freebsd-stable about trying to tune i386 systems with
> 4GB of memory - you should search the list archives.

Thank you both for your similar answers. I learned a lot by studying the
mailing list archives and experimenting. After a lot of trials, I found
the solution:

On the 4 GB machine, I compiled the kernel with MAXDSIZ="(2048*1024*1024)"
to achieve a max data segment size of 2 GB. This seems to cause the
problems, maybe by a signed int overflow? Reducing MAXDSIZ helps.

Best regards

Konrad Heuer (kheuer2 at gwdg.de)  ____            ___  _______
GWDG                           / __/______ ___ / _ )/ __/ _ \
Am Fassberg                   / _// __/ -_) -_) _  |\ \/ // /
37077 Goettingen             /_/ /_/  \__/\__/____/___/____/
Germany