On Fri, Sep 04, 2009 at 10:50:20AM -0700, Matthias Birkner wrote: > The "old school" conventional wisdom says "swap = 2x RAM". The more > modern conventional wisdom seems to vary from "swap = 1x RAM + 4G" > to "swap = 4G regardless of RAM". > > So if you're running/managing a Linux HPC cluster, or you have > strong opinions on the subject, or you just want to comment :), I > love to hear you're thoughts.
For most HPC needs, you almost never want the HPC jobs to use swap for active processes. Typically, if swap is being used, that means Something is Seriously Wrong. You probably want enough for OS and non-job processes to be swapped if needed, but not enough that large-memory jobs start using it. You probably don't even need swap for the systems you describe. Also, for linux memory management, you might want to experiment with the settings for the sysctl vm.overcommit_memory and vm.overcommit_ratio, since that controls how the memory manager defines how much memory is available, related to the amount of swap. -- Jonathan Billings <[email protected]> _______________________________________________ Tech mailing list [email protected] http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
