What is Mailbox Database Copies in Exchange Server 2010?

Database Portability was the new feature introduced in Exchange Server 2007 which allows you to move mailbox databases between servers. This feature is enhanced in Exchange Server 2010 with a new name called, Database Mobility, where all copies of a database have the same GUID, unlike Exchange Server 2007.

As we know, clustered mailbox servers and storage groups have been removed from Exchange Server 2010, continuous replication now occurs at the database level. Microsoft has recommended some key characteristics of mailbox database copies, as described below:-

·         Databases can be stored on Mailbox servers that don’t host the active copy of a database.

·          Two copies of same database can’t reside on the same server.

·         Database copies are for mailbox databases only. Use public folder replication for high availability and redundancy of public folders.

·         Exchange Server 2010 allows up to 16 mailbox database copies on multiple Mailbox servers, provided all Mailbox servers should be grouped into a DAG.

·         All Mailbox servers in the DAG should be in the same Active Directory domain, but database copies can be on created in the same or different Active Directory sites or network subnets.

·         In-built Windows Server Backup utility backup only Active copies, but not passive copies. Use
Exchange-aware, VSS-based backup application for all databases backup.

·         All copies of a database must use the same path on each server containing database copies.

·         Mailbox database copies can be created at any point of time and distributed across Mailbox servers.