HP 3PAR Application Software Suite for Microsoft Exchange - Manual (Page 99)

7 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.
The Microsoft Exchange mailbox database uses three key file types for all operations:
•
Log file (*.LOG). A file in which transaction log records are stored.
•
Checkpoint file (*.CHK). Maintains information about the location in the transaction logs last
committed to the database.
•
Database file (*.EDB). Properties data file to store all user data.
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 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 recreate 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. To reduce disk space usage, it also truncates the log
after the log has been backed up.
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 recreated 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.
Advantages of Using Recovery Manager
Traditionally, databases are backed up to tape. Backing up to tape is a time-consuming task,
especially if the database is growing rapidly. Recovery Manager offers the following advantages
over traditional tape backup:
•
Creating virtual copies of databases using Recovery Manager requires only seconds and can
be accomplished via a click of the mouse through the Recovery Manager GUI, or by scheduling
Key Microsoft Exchange File Types 99