Determining the appropriate size for a TFS data tier VM

Question

I have a two-tier (app tier/data tier) TFS 2010 installation. The data tier is currently living on a box that is being used for other things aside from TFS. My plan is to move to a VM which would be dedicated solely to TFS. It'll run SQL 2008 R2 and SSRS, with only TFS and SharePoint databases being on the box.

My questions are:

1. What metrics should be captured to determine the load on the server?
2. Are there any other things that should be considered?

Answer 1

Number of projects , size of projects check in frequency # of branches per project and number of developers per project. Last environment I had set up was 60 teams 5 - 8 branches per team with an average of 10-15 developers heavy usage running on an 8 core 48 gb server no issues.