After an Architectural Design Session provides you with a clear understanding of the solution and helps form your strategies surrounding hosted service offerings and timeline, a sizing session is the natural next step. And, because every hosted environment has specific needs that cannot be addressed by general sizing rules, the Sizing Tool provides a starting point while sizing for Microsoft Hosted Messaging and Collaboration. The Sizing Tool takes into account several sizing factors including communication protocols, concurrency rate, IOPS, and megacycles per mailbox per second.

The Hosted Messaging and Collaboration Sizing Tool and accompanying Hosted Messaging and Collaboration Sizing Guide evaluate your "sizing factors" to provide guidance on rules and tools needed to size your environment and start your deployment. The Sizing Tool and Sizing Guide facilitate:

• Discussions during sizing workshops.
  
• Collections of sizing information.
  
• Licensing costs estimation.
  
• Architectural drawing.
  

You can obtain the Hosted Messaging and Collaboration Sizing Tool at Operations Templates.

Note:
The sizing tool shipped with is an unsupported beta version.

The Sizing Tool is a Microsoft Excel file in which you discover and input your sizing factors and then evaluate the result. A typical Sizing Tool session includes three major phases:

• Collect sizing factor values.
  
• Apply the sizing factors to the tool.
  
• Refine and review the output.
  

For more information on how to conduct a Sizing Tool session, see the Hosted Messaging and Collaboration Sizing Guide that you downloaded with the Hosted Messaging and Collaboration Sizing Tool.