Question: What are the new server roles for Exchange Server 2010 and how do they match up with Exchange Server 2003?
Exchange Server 2007 introduced a new roles-based server architecture that is continued with Exchange Server 2010. An Exchange 2010 server is installed only with the roles you choose (with some limitations that I'll go into shortly) instead of being installed with the entire Exchange Server 2010 product.
This approach means that Exchange 2010 servers are easier to configure, easier to secure, easier to maintain, and easier to size for hardware.
The server roles in Exchange Server 2010 are:
- Mailbox Server – hosts the mailbox and public folder databases
- Client Access Server – provides connectivity for clients (eg Outlook, Outlook Web App, ActiveSync) to mailboxes
- Hub Transport Server – responsible for all mail flow in the organization
- Edge Transport Server – a special transport server intended for installation in DMZ networks to provide secure inbound/outbound email flow for the organization
- Unified Messaging Server – provides voice mail and other telephony integration with Exchange
So how do these roles match up with Exchange Server 2003?
- The Mailbox server is basically the same as an Exchange 2003 server that hosts databases (though Exchange 2010 has very different high availability features)
- The Client Access server is similar to an Exchange 2003 front-end server
- The Hub Transport server is similar to an Exchange 2003 bridgehead server
- The Edge Transport and Unified Messaging roles are new and don't closely related to Exchange 2003
Exchange 2010 servers can be configured with multiple server roles.
- Small environments often install a “Typical” Exchange 2010 server running the Mailbox, Client Access, and Hub Transport roles
- Medium sized environments often install the Hub Transport and Client Access roles together, but separate from the Mailbox servers
- Large organizations tend to separate servers into dedicated roles so they can scale appropriately
- Unified Messaging is not all that common in my experience so far but will co-exist with the Mailbox, Hub Transport, or Client Access roles
- Edge Transport servers can't co-exist with any other server role
To read more about Exchange Server 2010 server roles on Microsoft TechNet click here.