Microsoft Exchange 2010 introduced improvements to archiving, retention, discovery tools, backup processes, and online mailbox moves. It transitioned from a storage group model to a database availability group (DAG) model for high availability and introduced role-based access controls. DAGs use log shipping between up to 16 servers to provide redundancy without shared storage. Other new features included improved Outlook Web Access, remote PowerShell management, and support for 64-bit platforms only.