Is swap really needed when RAM's aplenty

Wed Aug 18 11:28:29 UTC 2010

On Wed, Aug 18, 2010 at 1:00 PM, Sam Varshavchik <mrsam at courier-mta.com> wrote:
> I'll probably have a new server with 16 gigs of RAM on the way, soon.
>
> With this amount of RAM being sufficient, do I really need a swap partition
> set up? I do understand that a swap partition is needed for hibernation, but
> this server does not need to hibernate.

On servers I normally use strict overcommit mode to not fail any
memory claims which are already mapped. Swap just raises the
CommitLimit, so that I am able to commit more memory (see
kernel-doc/Documentation/vm/overcommit-accounting and fs/proc.txt on
meminfo).

When using heuristic mode you certainly don't need to use swap but
have a higher risk of seeing the out of memory handler kick in
earlier. In a lot of situation the kernel is able to page out
not-needed memory to disk to have more room for I/O buffering
(swappiness) thus improving performance.