Application Server: additional JBoss servers
After several benchmark runs, all hardware servers involved in the benchmark might be running far below their capacity and JBoss might not be responding positively to any tuning. Providing there are plenty of network, memory and CPU resources available on each of the hardware servers e.g. less than 50% utilized, it might be time to add an additional JBoss Server instance. The additional JBoss instance should be able to process transactions close to the initial JBoss Server. For example, if one JBoss Server can handle an IR of 40 adequately, two JBoss Servers should be able to handle an IR of ~80.
As more JBoss Servers are added, it is less likely for them to scale linearly. For example, if our two example JBoss Servers can handle an IR of ~80, a third JBoss Server may only allow an IR of 100.
As more JBoss Servers are added, more pressure will be placed on the network, CPUs and database. Although some of these areas can be tuned, there will be a point where no more capacity can be utilized.