apache virtual memory usage on linux

I am running Apache 2.0.54 on Debian Sarge, and I was wondering about
memory usage.

Right now, Apache is running with mod_php5 and mod_rewrite using
prefork.c and is consuming around 6-8 Mb per process (max_spare is set
to 5). I am anticipating some heavy traffic and only have burstable RAM
of 1 GB available on my VPS. At 8 Mb per process I could have to serve
around 100-110 connections, but I am concerned when I look at the VM
usage. VM usage is about 22 Mb per process. It is unclear to me whether
or not I need to use VM as my benchmark for process size or the actual
(6-8Mb) RAM used. This makes a huge difference for my max_connections
setting.

Any advice? Any ideas on reducing VM usage or on getting the 6-8Mb
lower?

Thanks

[ fraz ]

> I am running Apache 2.0.54 on Debian Sarge, and I was wondering
> about memory usage.
>
> Right now, Apache is running with mod_php5 and mod_rewrite using
> prefork.c and is consuming around 6-8 Mb per process (max_spare is
> set to 5). I am anticipating some heavy traffic and only have
> burstable RAM of 1 GB available on my VPS. At 8 Mb per process I
> could have to serve around 100-110 connections, but I am concerned
> when I look at the VM usage. VM usage is about 22 Mb per process. It
> is unclear to me whether or not I need to use VM as my benchmark for
> process size or the actual (6-8Mb) RAM used. This makes a huge
> difference for my max_connections setting.
>
> Any advice? Any ideas on reducing VM usage or on getting the 6-8Mb
> lower?

You've read the docs on tuning Apache, yes?

http://httpd.apache.org/docs/2.0/misc/perf-tuning.html

Memory usage is very application specific, so I would turn to the
PHP-docs and -usergroups for help on that bit.


Rgds,
Kenneth Svee