Hi

> ... some of the system that I need to convert have as many as 50

concurrent users
vs

> We will be using Tomcat and JDBC to access the database.

So you have 50 concurrent users on tomcat and tomcat will have a connection
pool to firebird.
So the database will not have 50 concurrent users.

We have a system witha database of about 1 gb, with 35000 users, up to 200
concurrent but not very active, being 150 of them anonymous.
Every servlet is designed for maximum speed. Maximum tomcat load is at about
20 concurrent requests, maximum firebird load is at about 5 concurrent
connections though. (We keep security and basic configuration information in
memory and only access the database to propergate changes and to access
seldomly used information.) Our server cpu usage is at about 3% average and
10% on higher loads. We simply require lots of memory (>0.5GB for
system/firebird, >0.75GB for JVM).
But memory is cheap these days.

Regards,
Steffen