In Exchange Server 2007 you could use Exchange Server to provide email storage and the Microsoft Office Outlook client to access it. The Exchange Server 2007 client and server used the concept of User Store
The use of mailbox size limits in Exchange Server 2007 was a feature that was often abused by mailboxes that were too small for the mailbox in use. Exchange Server 2010 takes the concept of mailbox size limits to a new level. In Exchange Server 2010 the mailbox size limits are applied at the database level, and not to individual mailboxes.
With Exchange Server 2010 and the MDA, each of the mailboxes in a VPM is a database on its own. This means that the storage requirements for the VPM can be significantly less than for Exchange Server 2007.
The changes in Exchange Server 2010 are designed to take more advantage of the multi-core performance of modern multi-processor systems. The Multi Database Architecture (MDA) in Exchange Server 2010 allows for the creation of multiple mailboxes in the same database. This is done through a database partitioning scheme, that allows multiple mailboxes to be stored in different databases, and there is no need to create or modify the database schema.
Additionally, Exchange Server 2010 provides the possibility to aggregate Exchange mailboxes into a Virtual Private Mailbox (VPM). A mailbox can be used as a VPM, and this gives the ability to have many mailboxes in a single VPM. In Exchange Server 2007 this was possible using the concept of the mailbox database, but only in Exchange Server 2007.
The availability of VPMs will allow for the creation of a mailbox without an associated mailbox database (such as a mailbox with a size limit of zero). A VPM uses the Storage Location of a mailbox database, and therefore, the mailbox database can be on a different server or located on a different network.
The Technical Requirements and Information for Exchange Server 2010, with a guide to configuring the Exchange Server 2010, is available at http://www.microsoft.com/technet/exchange/server2010/technical/default.mspx . 827ec27edc