Originating Author: David Floyer
Exchange administrators have always walked a tightrope between the size of the Exchange database and the length of the backup windows. The size is kept down with often draconian limitations on the amount of space that users were allowed and the length of time that emails could be kept.
These restrictions create a problem for users – how to keep the ability to access these emails. The result was the start of the .pst file plague, which occupies masses of hard disk space on PCs and file and print servers. In one large pharmaceutical company, about 50% of the file and print space was wasted on .pst files. Once the user has created the .pst file, he cannot get rid of them. This is a financial burden, a productivity killer, and a business exposure to legal discovery.
Volume Shadow Copy Service (VSS) implemented in Microsoft Windows Server 2003 allows open files to be backed up. Exchange 2007 goes further and supports array-based snapshots using VSS; this enables many backup copies to be taken during the day. In general an array-based snapshot takes significantly less time to restore a backup, and because they can be more frequent, it is easier to pick a specific time (say 2pm) to restore a backup. As a result, larger databases can be restored more quickly and still meet the enterprise RPO/RTO requirements for email.
Action Item: IT executives should persuade the business to spend IT budget on significantly improving backup/restore capabilities for large Exchange databases with VSS and Exchange 2007. They should use these capabilities to remove user constraints on email management, and together with other solutions (e.g., email archiving) aim to obviate the need for users to keep .pst files. User productivity and risk reduction will more than justify this strategy.
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