[Beowulf] disabling swap on cluster nodes?

Egan Ford egan at sense.net
Sun Feb 8 16:10:10 PST 2015

Been swap free since 2005.  Various systems and sizes, including the
first sustainable 1PF system.  Since the systems were diskless and
stateless it made sense.  Yes, systems can crash if out of RAM, but
with stateless provisioning you just reboot.  Personally I'd rather
have a crash, rapid reboot stateless provision, and let another user
get the node, than a job start to crawl and waste time on the system.
Eventually the resource manager will kill it anyway for running out of

Anyway, that is my HPC baremetal answer.

For virtualized I found that swap enabled me to pack more work on to
fewer resources because I could safely overcommit the RAM.  OTOH, that
was not for HPC workloads.

On Fri, Feb 6, 2015 at 3:35 PM, Prentice Bisbal
<prentice.bisbal at rutgers.edu> wrote:
> Do any of you disable swap on your compute nodes?
> I brought this up in a presentation I gave last night on HPC system
> administration, but realized I never actually did this, or know of anyone
> who has. I would tweak the vm.overcommit_memory setting, but that's not the
> same as disabling swap altogether. I'd like to try doing this in the future,
> but I prefer to learn from someone else's mistakes first.
> --
> Prentice
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