Backup Operations

Creating applications that backup Microsoft Exchange Server 2010 data using the Volume Shadow Copy Service and the Microsoft Exchange Server 2010 Writers for the Windows Server 2008 Volume Shadow Copy Service limits you to one of the following types of backup operations.

Full	Backs up the databases (*.edb), transaction logs (*.log), checkpoint files (*.chk), and then truncates the transaction logs for a specific database.
Copy	Backs up the database (*.edb), transaction logs (*.log), and checkpoint files (*.chk). Copy backups do not truncate the transaction logs for the database.
Incremental	Backs up the transaction logs (*.log) to record changes since the last full or incremental backup, and then truncates the transaction logs.
Differential	Backs up the transaction logs (*.log) to record changes since the last full or incremental backup, and does not then truncate the transaction logs.

To better abstract the backup operation from the underlying file system structures, the VSS defines backup and restore components. The exact level of file or database granularity is controlled by the application through Writers. The components defined by the Exchange writers represent the database files and transaction logs within Exchange Server 2010 databases. This granularity allows backup/restore applications to display the names of the components within an Exchange Server 2010 database during backup operations and to additionally select the names of components within an Exchange Server 2010 database during restore operations. Only whole databases can be selected for backup; the underlying database and log components are provided for backup applications only to inform the user what components are included in the backup.

The Exchange writers standardize the database component logical paths. They are specified in the Exchange writer metadata and are returned to the requesting backup/restore application by the Exchange writers as needed. Logical paths provided by Replication Writer include an extra qualifier to designate the components surfaced by the Replication Writer.

The Store Writer provides logical paths in the form: logicalPath = “Microsoft Exchange Server\Microsoft Information Store\<Server name>”. The Replication Writer lists the logical path as: logicalPath = “Microsoft Exchange Server\Microsoft Information Store\Replica\<Server name>”

The server and database components are file group components, but do not have any associated files. Rather, the server and database components have sub-components that specify the individual files. There is only one log component in a database and its component name is Logs. The component names of the individual database components are the GUIDs of the databases, shown as strings. The component captions are the display names of the databases, as they are displayed in the Exchange System Manager.

Exchange metadata lists only the backup-able databases based on VSS framework guidelines. Databases that are mounted as the Exchange 2010 Recovery Database, as well as databases that are not mounted are not considered backup-able, hence are not listed in the Store Writer’s metadata. The same logic applies to database copies that are maintained by the Replication Service: any replica copy that is not in a “healthy” state is not considered backup-able and will not be listed in the Replication Writer’s metadata