As I mentioned in a tweet recently, we had a client reach out to us who had implemented ColdFusion 9 and ehcache and they were experiencing performance and stability issues in their application.  This point I belabor often, please load-test your code before deploying it, I am not a dictator in any way but this is just such a key issue.  

ColdFusion 9 introduces many new features two of which are integration with ehcache and also Hibernate ORM both features "out-of-the-box" use the same JVM heap memory as ColdFusion.  In a 32-bit install we have no more than a maximum of 1.4GB that can be allocated to the JVM Heap, when we add ehcache and ORM to the same heap as CF we could hit memory management issues in 32-bit systems and this is not idle theory, we have already observed this issue. One possible way to alleviate this is to have ehcache running in another JVM but the caveat is you have to communicate with ehcache via REST or SOAP which will slow things down; sort of Catch-22.

Our recommendation is to have more memory available to the JVM heap from the outset.  The easiest way to do this is to have a 64-bit system with ColdFusion 9 64-bit.  In that situation we could have up to 32GB RAM available to the JVM heap instead of just 1.4GB.  I have re-stated this several times in my presentations, please go with a 64-bit system, with a 64-bit ColdFusion version and I would further recommend at least 8GB Ram in the system.  

If you need any assistance with establishing load-testing to verify all of this please contact us.