[Gllug] performance difference between a swap partition vs a swap file.>>>>>

Richard Jones rich at annexia.org
Wed Dec 2 16:44:56 UTC 2009

On Wed, Dec 02, 2009 at 10:47:54AM +0000, Alex Smith wrote:
> Alain Williams wrote:
> > Swap is good for things like 'getty' that are started and hardly ever used.
> > It is also good for when something goes wrong and starts eating RAM,
> > gives your system a chance to live until you sort things out.
> In this situation, wouldn't you want your getty to definitely not live 
> in swap, just in case you need to get on the system from a conosole and 
> sort things out?

What you'd really want in this case is some way to lock the relevant
parts you need into physical RAM.  The kernel is already "locked" in
RAM, so you'd have to mlock pages from getty too.  And login, and
bash, and any diagnostic programs.  Never seen this done in real life
though :-)  People who want such highly available systems tend to
configure them without swap and without memory overcommit in the first


Richard Jones
Red Hat
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