In the event of a major catastrophe, you may need to restore Microsoft Exchange Server databases from tape backup. There are two scenarios when the information store and directory must be restored:
Restoring individual mailboxes on a Microsoft Exchange Server computer can be a long and arduous process that requires extra hardware and time. Therefore, it is imperative that you set a policy for restoring individual mailboxes. Without a policy, mailbox restores can be overwhelming.
Microsoft Outlook provides several options to guard against the accidental deletion of messages. Users can protect themselves from simple mistakes by using the Deleted Items folder and either emptying it manually or emptying only when the client is closed.
With Microsoft Exchange Server 5.5, users and administrators can also take advantage of a feature called Deleted Items Retention. This feature allows administrators to configure their public and private information stores to retain deleted items for a specified number of days before they are permanently deleted. Using Microsoft Outlook version 8.03 (or 8.0, 8.01, or 8.02 with the proper client extension installed), users can retrieve items deleted over the past number of days as configured by administrators. This feature alone can serve as the basis for a restoration policy, such as, "We'll retain deleted items for 3 days, after which they will be purged from the system." Of course, you can make exceptions for the occasional vice president or CIO/CEO whose mail is accidentally deleted.
Other successful organization messaging services departments require that departments requesting individual mailbox restorations must pay a standard fee. These charges range from $100 to $250 per mailbox restored.