recommendation for swap space?

[C. Handel]

On Mon, Apr 7, 2008 at 6:18 PM, Michael S. Fischer <michael at dynamine.net> wrote:
>  >  > now that my varnish processes start to reach the RAM size, I'm wondering
>  >  > what a dimension of swap would be wise? I currently have about 30 GB
>  >  > swap space for 32 GB RAM, but am wondering if it could even make sense
>  >  > to have no swap at all? My cache file is 517 GB in size.
>  >
>  >  Varnish does not use swap.
>
>  That said, it wouldn't make sense to entirely deallocate your swap
>  space, since the kernel may decide to page or swap out processes other
>  than Varnish.

You also need swap if a huge process tries to fork. Having a huge
Process forking a child, means, that the child process initially is a
copy of the parent. It is a copy on write memory (so it doesn't realy
use memory) and in most cases the child will release all memory and do
something else, but the virtual memory needs to be big enough during
the fork.

Greetings
   Christoph