Matthias Birkner wrote: > At $work we've been having a discussion about what the right amount of swap > is for a given amount of RAM in our standard linux image and I'm looking for > additional input. > > 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. > > Some info about our environment... We have several HPC clusters scattered > around the globe with anywhere > from 100 to somewhat over 1000 systems in each cluster. Workload in > the clusters is managed using LSF and typically they are configured to > have one job-slot per cpu. The memory configs in each system ranges > from 4G RAM up to 512G. Not sure if the OS version matters but in case > it does, we're primarily running RHEL4u5 and starting a migration to > RHEL5u3. > If HPC speed is important, and it sounds like it is, you never want to swap because it will kill you. So, to some extent, it doesn't matter, it's kind of like asking what color the deck chairs should be on the titanic; you know it's going to sink, so whether they are blue or green seems picayune.
That said, we use swap = mem. (we have way more disk space on the cluster nodes than will reasonably be used, so making it larger doesn't matter either) _______________________________________________ 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/
