To optimize performance, operating system and WebSphere Application Server paramaters are automatically tuned in the IBM® WebSphere® Application Server Hypervisor Edition virtual image.
WebSphere Hypervisor Edition automatically tunes application servers and deployment managers based on the virtual resources allocated to the virtual image. The automatic tuning attempts to optimize your virtual system for performance, but can easily be changed to meet the specific needs of your application. The Java heap size is sized based on the allocated virtual memory, WebSphere Application Server web container threads are sized based on the number of virtual CPUs.
Minimum/Maximum JVM Heap = max(min((Virtual Memory - 1280MB) / # Application Server Instances, 4096MB), 256MB)Based on the amount of virtual memory allocated to a virtual image, the intent is to distribute as much memory as possible to each application server and deployment manager instance. After reserving 1280MB for the OS and other native processes, the remaining memory is divided evenly between JVMs. The automatic tuning algorithm will assign no less than 256MB, and no more than 4GB for a given JVM.
Minimum/Maximum Threads = # Virtual CPUs * 10A factor of 10 modifies the number of web container threads according to the number of virtual processors in the virtual image. The purpose is to provide additional worker threads to effectively utilize systems with more virtual CPU resource.