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Ever since Microsoft announced its new licensing policy for virtualisation, I’ve been trying to get an answer on whether the “4 free guests with every copy of Windows Server 2003 R2 Enterprise Edition (or unlimited guests with DataCenter Edition)” applies when non-Microsoft virtualisation products are in use.

Various Microsoft representatives have indicated to me that to restrict it to Microsoft virtualisation products would not be possible but no-one seemed 100% certain on the answer and I didn’t want to place myself in the situation where I advised a client that they had sufficient Windows licenses when in fact they were under-licensed. Earlier today I found the VMware pricing and licensing FAQ: Microsoft licensing for virtualised environments which answers my question, although it is also heavily caveated:

“This document is provided solely as a convenience for VMware employees, partners, customers and prospects and does not constitute legal advice. Your review of this FAQ should not substitute for review of applicable Microsoft licensing agreements and documentation”

Basically, it looks as if the Microsoft licensing arrangements apply regardless of the virtualisation product in use - in fact you don’t even need to have Windows installed on the host server - as long as an appropriate Windows license is owned (so ESX Server users can run 4 Windows instances free of charge, provided that they also own a “spare” copy of Windows Server 2003 R2 Enterprise Edition).

Another licensing issue that’s been concerning me is VMware’s model of licensing server products such as Virtual Infrastructure 3 by pairs of physical processors (2 sockets). For example, a 4-way HP ProLiant DL585G2 with 4 dual-core AMD Opteron CPUs would need 2 licenses (2 x 2 sockets) even though there would be 8 logical CPUs. With the imminent arrival of quad-core CPUs and predictions of many more cores on future processors, I had to wonder how long this model could be sustained and VMware has provided a clue to the answer in the VMware multi-core pricing and licensing policy. Basically, it seems that 4 cores is the breakpoint:

“[VMware’s] policy defines a processor for licensing purposes as up to four cores per processor.”

So, any future 8-core CPU could be expected to use up 2-processor’s worth of VMware licenses. Confused? Well, even VMware are reserving judgement:

“This policy applies only to dual- and quad-core processors. VMware will revisit its licensing policies as x86 processors with a greater number of cores become available.”

There’s more information about multicore processors on the Intel and AMD websites.