Large memory issues on 4-STABLE

[Irvine Short]

Hey All

I have a dual Xeon box used by our students for data crunching. It has 4GB
of RAM.

After initial installation everything went well until someone found they
couldn;t allocate more than 512MB of RAM per process. After some poking
around I found some things things to adjustin the kernel conf file:

options         MAXDSIZ="(2000*1024*1024)"
options         MAXSSIZ="(128*1024*1024)"
options         DFLDSIZ="(512*1024*1024)"

Now here's the problem, consistent with  three versions of 4-STABLE over
the last couple of weeks and finally yesterday.

Everything works perfectly as abve except that limit reports datasize
2048000 kbytes - which kind of makes sense given the figures above.

However, the guys want to be able to use all the RAM, not just 2GB

If I increase MAXDSIZ to 2048 then limit reports datasiz unlimited but
mysql will not run, unfortunatly I've lost the log file from then but it
was something like a pthreads error 36 - mysql would just start up and
shut down.

Other than that though the machine ran fine.

If MAXDSIZ is set to 4096 then the kernel will not even load, if it's set
to 4095 it gets part way through the rc scripts and then crashes.

3500 gets you almost but not quite booted - all kinds of apps failing
unable to allocate memory.

Any help would be much appreciated - it's a production box and I don't
have anothe 4GB box to play with.

Cheers,

Irvine Short

Sys Admin
SANBI, University of the Western Cape, South Africa
http://www.sanbi.ac.za
tel: +27-21-959 3645
cel: +27-82-494 3828