[Beowulf] size of swap partition

Guilherme Menegon Arantes garantes at iq.usp.br
Tue Jun 10 06:53:15 PDT 2008

On Tue, Jun 10, 2008 at 06:13:00AM -0700, beowulf-request at beowulf.org wrote:
> Date: Tue, 10 Jun 2008 00:58:12 -0400 (EDT)
> From: Mark Hahn <hahn at mcmaster.ca>
> Subject: Re: [Beowulf] size of swap partition
> To: Gerry Creager <gerry.creager at tamu.edu>
> Cc: Mikhail Kuzminsky <kus at free.net>, beowulf at beowulf.org
> it is possible to tune how the kernel responds to memory crunches - 
> for instance, you can always avoid OOM with the vm.overcommit_memory=2
> sysctl (you'll need to tune vm.overcommit_ratio and the amount of swap
> to get the desired limits.)  in this mode, the kernel tracks how much VM
> it actually needs (worst-case, reflected in Committed_AS in /proc/meminfo)
> and compares that to a commit limit that reflects ram and swap.
> ...
> their real/virtual ratio.  the kernel only enforces RLIMIT_AS
> (vsz in ps),assuming a 2.6 kernel - I forget whether 2.4 did 
> RLIMIT_RSS or not.

And that brings me to another related question: Where I can get more
information about VM usage/tunning options (such as vm.overcommit_ratio, 
RLIMIT_AS, etc) and VM metrics (such as vmstat) for the current linux 
kernels (>= 2.6.18)? I have looked on /usr/src/linux/Documentation/vm 
but anywhere else with more accessible/digested info?




Guilherme Menegon Arantes, PhD       São Paulo, Brasil

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