Giving your users the ability to store more e-mail has many advantages. Large mailboxes keep e-mail and e-mail archive on the Exchange Server instead of allowing it to be scattered in Outlook Data Files (.PST files), which often lead to corruption of data. That helps reduce the risk of data loss, improve regulatory compliance, and increase productivity among both workers and IT staff. The main barrier to implementing large mailboxes is the perceived cost and complexity of storing large amounts of e-mail data.
Microsoft® Exchange Server 2010 is specifically designed to overcome these barriers. It enables you to give your users larger mailboxes at lower cost without sacrificing performance or reliability. Built-in high availability, by using DAG, and disaster recovery, storage system improvements, and self-healing from disk faults let you use large, inexpensive disks in configurations that maximize data redundancy. And, Exchange Server 2010 lets you keep your users online during mailbox moves. With these changes, the benefits of large mailboxes are now within the grasp of all organizations.
The new database model has been enhanced so that the writing is done on a sequential manner, allowing the Exchange Server 2010 to use SATA Hard-drives. This is a major improvement as it allows to reduce storage costs.
Please read the Withepaper and find out more about these changes.