On 10/23/07, Dave Jones <[EMAIL PROTECTED]> wrote: > Well, my colleague Rob v.d. Heij beat me to the punch line, but this was > where I was headed....having more than one JVM inside a Linux guest is, > imho, asking for trouble. Is there a reason you need to have multiple > JVMs running at the same time?
The two managers I referred to was the memory management in the JVM heap (based on garbage collection) and the memory management in Linux (based on LRU). And to complete the picture, you also have z/VM manage the virtual machine and swap space. Ideally you only want one such layer to manage things. But for dealing with peaks you need more. For example, you allow z/VM to page in a virtual machine when work starts, but when it is working there should not be a lot of paging. Running multiple applications in a single virtual machine makes it harder for z/VM to determine what resources are needed. That holds for running two JVM's with different resource requirements, but also for other applications. In one of the redbooks we demonstrated that breaking up a 3-tier application into 3 virtual machines (HTTP, WAS, DB2) was more effective than running them in one single virtual machine. Rob -- Rob van der Heij Velocity Software, Inc http://velocitysoftware.com/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
