Understanding single and multi-role server installations

Although you can deploy each server role on a single server, we recommend that you deploy multi-role servers in certain scenarios. For example, deploying a single Exchange 2010 server role on a standard server with multi-core processors might leave a large portion of available CPU underutilized. If you consider the number of mailboxes that can be supported by the IOPS provided by current disks, the Mailbox server role by itself generally won't use more than half of the available CPU resources. Adding the Client Access server role and the Hub Transport server role to this server will use the capacity of the server more effectively. There are also certain scenarios where we don’t recommend installing multi-role servers. For example, multi-role servers may not work well for small deployments where two or three multi-role servers are being deployed as members of a database availability group (DAG).

For more information, we suggest that you review the following topics before you proceed:

• Understanding Multiple Server Role Configurations in Capacity Planning

• Understanding Client Access and Hub Transport Combined Role Configurations in Capacity Planning

• Understanding Server Role Ratios and Exchange Performance