I do a lot of virtualization work and I frequently am asked about how virtualization relates to capacity planning of specific solutions. I find it really interesting to plan for capacity in virtual environments, as the translation from "hardware" requirements to "virtual hardware" requirements are somewhat hard to equate. As an architect, virtualization actually provides me a much less artificial context in which I can specify requirements, since rather than talking about servers, off which there are only so many iterations, I have the opportunity to "slice and dice" specific hardware components to fit the requirements of the solution specifically.
In Lync 2010 Microsoft announced support for virtualization of any and all roles. That said, with a service as important as voice, companies are understandably cautious. An important question to be asked is "how does virtualizing Lync affect capacity planning"? Fortunately, Microsoft understood that this was a very important planning consideration, so they've produced the following grid, which outlines the user capacities and hardware expected in physical and virtual environments:
- The maximum cores in the virtual environment is 4. This changes the framework of Lync to "scale out" vs. "scale up". I've found that this approach in Lync, as well as other platforms allows for much more effective use of computing resources.
- Approximately half of the users / calls per server.
- Standard edition. Initially Microsoft did not support Lync Standard Edition virtualized. This stance has now changed and is fully supported.
Recommended Host Information:
- Enterprise grade (major vendor), with two sockets.
- Intel 5500 series / AMD Opteron 6 or greater
- Two or more 1 Gb adapters or 10 Gb. Note that if you are building a Hyper-V cluster, you should have more. See my article on Hyper-V networking best practices: http://www.concurrency.com/blog/hyper-v-networking-best-practices/
- Storage and RAM for VMs allocated.
Note the following Microsoft site: http://technet.microsoft.com/en-us/library/gg399035.aspx
More information on virtualization support: