Install JTS and RTC on same host, with WAS as appServer, as 2 JVMs or 1 JVM?
Getting help from in-house WAS team to install 6.0.4 JTS and RTC on same host: One of their question was should they be installed as 2 JVMs or 1 JVM.
One answer
If you install JTS and RTC into separate WAS profiles, you can treat it as a "distributed" environment, even not fully. So you will need a reverse proxy as well. The JVM heap requirement is not actually a rule of thumb. What we want is to allow enough memory for the OS (and other applications, such as DB) to run. If everything runs in the RAM, it can be fast. When some applications/binaries have to be paged out to the swap space (hard drive), the performance start to degrade.
I have seen an environment with more than 100GB memory, and many WAS profiles running on it, with the JVM heap being 4GB to 16G for each profile - just give you an idea.