On 11/2/07, Gary Sewell wrote:
> Firstly, we are running a mod_perl application on 4 separate servers due to
> its bulkiness.


Do you have a lot of traffic? Most people don't need this many
servers if they run a reverse proxy in front of mod_perl.

> We have found each apache instance is almost double on the 64-bit servers


I think this has to do with how you compile perl. There was some
discussion in the list archives. Try searching the archives and maybe
Google the archives for comp.lang.perl.misc or p5p too, since it's a
general perl issue and not a mod_perl thing.

> Is it worth installing a 32-bit distribution on the 64-bit processors? Will
> the 8Gb RAM cause problems as 32-bit distributions if we did this?


You won't be able to use most of that RAM if you run a 32-bit OS.

> How can I get a split/rundown of what is taking up so much memory for each
> apache instance, 100Mb is a lot, let alone 200Mb on the 64 bit servers. I'm
> sure we are going wrong somewhere.


100MB is a lot bigger than normal for a mod_perl app, IMO. Are you
caching some data or something?

You'll find most of the collected wisdom on how to analyze your apps
in the Practical mod_perl book:
http://www.modperlbook.org/

- Perrin