The suggestions provided are valuable.
I am looking at to exploit the unutilized CPU capacity (70 % [max affordable CPU utilization] - 40 % [Observed max utilization during peak load] = 30 % free) of the application server to handle even more concurrent users.
For this if suppose I run two Jboss instances (clustered) in the same box with reduced heap sizes and accordingly adjust other associated JVM tuning parameters, would it be possible to have an increase in number of concurrent requests (sum of requests that can be handled by individual instances, or better approximation - sum of 'maxThreads' of both instances) that can be served by the Server?
Motivation to think in the above respect:- Have come across a rule of thumb for calculating the value of 'maxThreads' -> [200 * No. of CPU] +/- depending on RAM and other Machine specs.
Does this rule apply for each instance of Jboss running on the server? or it applies to the server as such, irrespective of how many Jboss instances are running in it?