NONMEM Virtualization

Hi, I know that this topic has come up from time to time, but I've not found a definitive word on using NONMEM in virtualized environments. If I've missed an old post here, please point me to the link I should have found. Specifically I have a few questions for people who have built virtualized NONMEM clusters: * As most of the readers of this list are probably aware, when there is a very stiff problem, it is possible to get different results on different CPU/OS/compiler combinations. When a virtualized system (where the OS and compiler are held fixed) executes NONMEM on the same CPU I would assume that identical results would come out. Do people have experience with stiff problems on virtualized systems with different underlying physical CPUs? Does it give the same or different answers for such models? * I know that current virtualization systems are pretty good about not getting in the way very much for raw CPU power and IO/sec. Do people have an idea on identical hardware how much the virtualization system adds to the time to complete a NONMEM run? Hopefully there can be a few answers here with different virtualization platforms (VMware, KVM, Xen, ...). * I've heard that the next version of NONMEM will support parallelization within a run. I realize that people won't have experience with this, but I was wondering if there are any hints of about how well it will scale? Will it scale well to a fixed number of CPUs? Will it scale well proportional to the number of subjects, thetas, ...? Any hints on how many CPU/node would be optimal for a cluster? Any hints on how well NONMEM will work with virtualized multi-CPU machines? Thanks, Bill Notice: This e-mail message, together with any attachments, contains information of Merck & Co., Inc. (One Merck Drive, Whitehouse Station, New Jersey, USA 08889), and/or its affiliates Direct contact information for affiliates is available at http://www.merck.com/contact/contacts.html) that may be confidential, proprietary copyrighted and/or legally privileged. It is intended solely for the use of the individual or entity named on this message. If you are not the intended recipient, and have received this message in error, please notify us immediately by reply e-mail and then delete it from your system.