Architecting a Hybrid Messaging Strategy with Microsoft Exchange 2013 : Designing the Solution : 7.2 Server Sizing : 7.2.2 Sample Environment Sizing
   
7.2.2 Sample Environment Sizing
By using the Microsoft Mailbox Server Role Calculator, Rainpole.com’s IT organization has determined that the following virtual machine requirements will be sufficient to meet the needs of the customer’s environment.
Table 4. Environment Sizing
Virtual Machine Role
vCPU
Memory
Exchange Mailbox VM
8 vCPU
48 GB RAM
Exchange Client Access VM
4 vCPU
16 GB RAM
Exchange Edge Transport VM
2 vCPU
8 GB RAM
 
Now that physical resource requirements of the customer’s environment and associated virtual hardware configuration are understood, physical resources can be planned to meet those requirements both on- and off-premises. To build infrastructure availability into the architecture, virtual machines will be distributed across multiple hosts on-premises and rely on the provider’s VDC resources to provide the same level of availability at the VMware Cloud Provider data center facility.