I want to make short and sweet (or bitter in that case). I have learnt a valuable lesson this week and I would like to share – The ONLY supported virtualization platform for MOSS is Virtual Server 2005 R2. That's right – you read correctly. Virtual Server 2005 is the only way to go virtual in MOSS. Forget about VPC 2007! Forget about Virtual Server 2005! And most importantly, forget about VMWare! Microsoft won't support any of those implementations on a production server.
Several months ago, one of our customers tried to "play against the rules" and go VMWare. He was reassured by the VMWare guys that told him he will receive "commercially reasonable" support. Ok, promises like that are hardly something that would make me sleep better at night but the customer was satisfied. VMWare MOSS was implemented.
This lasted up until now. We've recently bumped into a nice performance issue in one of the FE virtual servers. We knew it had nothing do with Virtualization since we tested it over and over and we decided to ask the big brother – Microsoft Services. Now, here's the catch – they told us to go physical before they'll inspect the problem. We tried to rebel that annoying decision (and again – we tested it and that was MOSS's problem and not virtually/physical issue) but there is nothing MS could do – this is exactly what "Not Supported" means!
Anyway, if you chose virtual to be your production server for MOSS – that's OK and it'll probably work fine. However, unless you are working with Virtual Server 2005 R2 – at any time, Microsoft PSS guys could ask you to go to physical hardware to aid in troubleshooting and there is nothing you can do about it. I urge you to take it into consideration before you decide on the full virtual architecture…