Random machine freezes when running several OpenFoam jobs simultaneously
 

Dear Foamers,

I am experiencing random machine freezes when running several (>6) OpenFoam processes on an 8-kernel computer (two quad-core processors) and I cannot figure out why this is happening. Maybe someone has had the same experience or an idea what might be going on.

A little background:

a) When I start > 6 OpenFOAM processes simultaneously the system completely freezes between 1 and 30 minutes later. This happens both when I run a parallel job or several individual jobs.
("Freeze" means no keyboard entry is accepted and the mouse doesn't move - I cannot even change to the basic shell with "ctrl-alt-F1" and no connection via network is possible.)

b) I am not observing this behavior with any other program (in particular parallel jobs in Mathematica and Comsol run for >12 hours using all 8 system cores without problems)

c) In particular I have been using icoFoam and simpleFoam as well as self compiled variants of these which also solve a scalar equation.

d) The same problem occurs under OpenSUSE 11.0 and the enterprise version SLES10-SP2.

e) I could reproduce the behavior with OpenFoam versions 1.5, 1.6 and also 1.3.

f) The jobs I used are not particularly memory intensive, so no wild swapping is going on.

g) Running only a few jobs works fine...

The computer I am using has two quad-core Intel-Xeon X5570 CPUs and 12 GB of RAM. I have been using the pre-compiled OpenFOAM binaries as downloaded from sourceforge (apart from the two customized solvers).

Any suggestions on how to overcome the problem are greatly appreciated!

Thanks,
Tobias Baier

I have the same problem, when I edit color map or legends. how I can kill the process when the keyboard does not function. If I wait, does it differ? I have not waited more than 10 min. I don't know if I wait more it gets out of the freeze condition

ssh in from another machine. If that doesn't work you have a serious problem

No idea about the original problem

Greetings mhassani,

You're experiencing problems with ParaView, not OpenFOAM in particular.
That usually happens when ParaView is not built with a valid Qt library version. Try downloading and using the official ParaView build: http://www.paraview.org/paraview/res.../software.html

Best regards,
Bruno

are you running the job over a network disk?

is it the same when you run them under /scratch?
is it the same when your foam installation is under /scratch?

N

Hi mhassani,

I never found out what really was the reason for my system hangups, but in the end concluded that is was most likely a hardware problem and that it was unrelated to OpenFOAM (I also occasionally got hangups when using some other software heavily).

Anyway, I believe you are experiencing the same problem but most likely for some different reason, since in particular you seem to get a hangup while using Paraview. Have you tried using "ctrl-alt-F1" to switch to a basic shell? If that still works, you might be able to abort paraview from there...

Best,
Tobias