https://bugzilla.novell.com/show_bug.cgi?id=687505 https://bugzilla.novell.com/show_bug.cgi?id=687505#c1 Petr Cerny changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |NEEDINFO CC| |pcerny@novell.com InfoProvider| |antonio.liggieri@poyry.com AssignedTo|pcerny@novell.com |bnc-team-screening@forge.pr | |ovo.novell.com --- Comment #1 from Petr Cerny 2011-04-19 10:00:17 UTC --- Antonio, could you please provide a more detailed description? From the initial bugreport it is hard to tell where the problem might be and it is definitely not descriptive enough to try to reproduce it. Are you using some special clustering framework or is it just your own set of scripts and applications scheduling the work? Isn't by chance some processes on the machine eating up all resources? In that particular case using cgroups might help you to ensure that important processes get at least some chance to run (see the following links for introduction if you are not familiar with the feature: http://en.wikipedia.org/wiki/Cgroups http://www.kernel.org/doc/Documentation/cgroups/ ) Screening: reassigning back - for now I don't see how I could help any more wioth this bug. -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.

https://bugzilla.novell.com/show_bug.cgi?id=687505 https://bugzilla.novell.com/show_bug.cgi?id=687505#c3 --- Comment #3 from Petr Cerny 2011-04-19 13:22:55 UTC --- (In reply to comment #2)

Basically the problem can be split in two sypthoms.

After setting up SSH for communcation between 4 maschines, where one of those maschines is set up as server, while the others as clients, the maschine set up as server,

1. changes the desktop charakteristics: by minimazing an application, the application disappears from screen.

Looks like part of the desktop environment (and I believe you are using KDE) gets killed

2. the shell doesn't react any more after while.

Ditto, only this time it might be KLauncher.

OpenFOAM @ 8 parts on 4 dualcore. The communication on network level is via MPI over ssh.

...

Cgroups In fact during the calculation the whole CPU power on all the maschines is required for it. But the strange thing is, that the problem is only on the maschine which is set up as the server. No problems at all with the clients.

Summing it up I would say, that the server machine is under a way too heavy load. Resource hungry calculations like CFD, FAE, MHD etc. are usually run on almost bare metal whenever possible. Things that might help (from the easiest to IMHO best): 1) Running the calculation on the server with a lower priority. 2) Switching off the GUI at least on the server would be the first thing to try (or at least changing to a less hungry one like XFCE or LXDE). Under some circumstances you might have the OOM killer destroy some applications unexpectedly. At least you'll get more memory for the essential tasks. 3) splitting the calculation into 7 parts instead of 8 and reserve one processor on the server for MPI and sshd. If the server also stores all the input/output for the computation clients, you won't get full 2 computational units anyway. Alternatively, add an additional computer (can be probably less powerful) to act as a coordination/data server for 4 clients doing the calculations. sshd might be resource consuming when serving more heavily communicating clients (remember that the links are encrypted and that comes with a cost). 4) I really suggest trying cgroups - it doesn't allocate the resources by default. Only when an application needs them, it gets them on the expense of others that would otherwise not give them away (i.e. even while doing the calculations you will be able to ssh into the machine). -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.