With the transition of workloads from dedicated server footprints to big machines which are logically partitioned or hosting hundreds of virtual guests, idle times in one guest or JVM may not necessarily translate to low-utilization of the entire platform. A typical development machine hosting hundreds of developer's guests may have many guests active, but idle. It is important that the idling machines impact overall system performance minimally.
We've written a whitepaper which focuses on how to configure WebSphere V7 to minimize idle-time processing available here. We hope you find the paper informative and helps you reduce the load of idling WebSpheres in your environment.