Good read from Microsoft. Source : http://blogs.technet.com/tonyso/archive/2009/11/30/hyper-v-how-to-plan-performance.aspx

Customers often ask “Given a hardware load-out X, how many Ys can I get/run/host?”

The frustrating answer always starts with “…it depends…”. We caveat this way not because we want to frustrate, but because it is true. Many teams will go on to say “We have tested the following in our labs and gotten the displayed results…”

1 X = thingy

2 X = more thingies

3X = many more thingies

While accurate, not super-helpful.

The truth is that to do good perf planning for Hyper-V you have to run some tests.

Run them using your actual production load (converted to Virtual Machines) in a test environment.

TIP: you can download the free VHD version of SCVMM, then run it as a VM to convert your production machines to “test” virtual machines.

Then play with your assumptions and tweak things higher and lower and to your design tolerance and actually observe how perf goes.

Add an overhead/forgot-to-test percentage, done.

So, how to do that for Hyper-V? Here are some perf testing resources to help you:

• Performance and capacity requirements for Hyper-V
• Hyper-V Performance FAQ
• Measuring Performance on Hyper-V
• Checklist: Measuring Performance on Hyper-V
• Performance Tuning Guidelines for Windows Server 2008
• Performance Testing Guide for Windows Paper
• Optimizing Hyper-V performance: Advanced fine-tuning
• Hyper-V Support, Performance and Load Tools
• Hyper-V How To: Set Up a Virtualization Test Lab using Windows Server 2008 Cluster, Hyper-V and simulated iSCSI…
• Hyper-V Server Sizing: How Much Memory for the Host?
• VM Perftuning: Minimize VM background processing
• Hyper-V How To: Balance VM I/O
• Monitoring Hyper-V Performance
• How to get Processor Utilization for Hyper-V via WMI
• Hyper-V Performance Counters – Part one of many – The overview
• Hyper-V Performance Counters – Part two of many – “Hyper-V Hypervisor” counter set
• Hyper-V Performance Counters – Part three of many – “Hyper-V Hypervisor Logical Processors” counter set
• Hyper-V Performance Counters – Part four of many – “Hyper-V Hypervisor Virtual Processor” and “Hyper-V Hypervisor Root Virtual Processor” counter set
• Hyper-V Performance Counters – Part five of many – “Hyper-VM VM Vid Numa Node

Disclaimer.
The information in this article is provided “AS IS” with no warranties, and confers no rights. This article does not represent the thoughts, intentions, plans or strategies of my employer. It is solely my opinion.