HP Application Software Suite for Microsoft Exchange manual Rapid Backup and Recovery for Exchange

8 Rapid Backup and Recovery for Exchange

Key Microsoft Exchange File Types

Before describing backup and recovery for HP 3PAR Recovery Manager Software for Microsoft Exchange, you must understand the elements of Exchange.

Microsoft Exchange uses these key file types for all operations:

•Log file (*.LOG). A file in which transaction log records are stored.

•Patch file (*.PAT). Used during backup, restore, and recovery operations, it contains database pages that were split during online backup.

•Checkpoint file (*.CHK). Maintains information about the location in the transaction logs that was last committed to the database.

•Database file (*.EDB). Properties data file to store all user data.

There are three key files within Microsoft Exchange storage groups: EDB, CHK, and LOG files. LOG files are accessed in a sequential order; EDB files are accessed with random I/O patterns. For optimal performance and to facilitate database management, transaction logs should be placed on a volume that performs sequential I/O in an optimal manner such as a RAID 1 volume. The EDB files should be placed on a separate volume that is optimized for random I/O such as a RAID 5 volume. For additional information on creating volumes, see the HP 3PAR InForm OS CLI Administrator’s Manual.

From the performance and management point of view, a dedicated volume should be created for every log file group on each mailbox database, and another data volume should be created for EDB files for each data store on every mailbox database. For example, if you have two storage groups, each with a log and five mailbox stores, create two RAID 1 volumes for the logs, and ten RAID 5 volumes for the EDB files.

When a change is made to the mailbox database, Exchange updates the data in the memory (32K pages) and synchronously writes a record of the transaction to the log in sequential order. This record allows Exchange to re-create the transaction in the event of a failure. The database engine then writes the data to the disk in large I/O operations. Exchange supports circular logging to save disk space on the volume containing log files. However, circular logging makes hard recovery (restoring from backup) impossible. Therefore, HP recommends that you disable the circular logging feature (circular logging is disabled by default in Microsoft Exchange).

Backup

An online backup of Exchange runs while the data store is mounted. A full backup backs up the entire information store and transaction log. It also truncates the log after the log has been backed up to reduce disk space usage.

Virtual Copies

A virtual copy is a copy of another virtual volume (EDB or LOG) created using copy-on-write techniques. Unlike a physical copy, which is a duplicate of the entire virtual volume, a virtual copy, or snapshot, only records the changes to the original virtual volume. Therefore, minimal storage space is used. This allows an earlier state of the original virtual volume to be re-created by starting with its current state and rolling back all the changes that have been made since the virtual copy was created. The system allows you to make up to 500 virtual copies of each virtual volume, assuming that sufficient storage space was allocated when the base virtual volume was created.

82 Rapid Backup and Recovery for Exchange