[Exim] calculating system requirements

I couldn't find anything on this. How do you calculate the system
requirements for both pop and imap mail with a MySQL or PostgreSQL
authentication backend (on the same computer)?

For example, if you have a small office with 50 persons and need to
set up an imap mail system, how fast and how much memory and still
get reasonable performance. The same system would be running exim,
the imap softare, mysql and other support programs. Toss in needing
apache to run a webmail system such as IlohaMail, how does this
affect the system requirements?

This is assuming an ipx86 Linux system.

Rossz
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Fogalmam sincs, mi van ide írva.