An important feature of email archiving is called “stubbing.” This is a process whereby an entire email or just the attachment is removed from Exchange and replaced with a “stub” file. When the user opens the message in Outlook, the stub file retrieves the archived email and/or attachment from the archive. The benefit is reduced Exchange storage.
Microsoft is now recommending against the use of stubbing:
- Search problems. If you retain months (and years) of stub files, several hundred thousand messages will be processed in this way. The probability of successfully locating a specific message with Outlook search is greatly reduced when you do not have a significant portion of the message body available. Users need to go to the archive multiple times to find a desired message. Third-party email archiving solutions solve the problem of mailbox size, but they reduce search efficiency and increase user time performing multiple searches.
- Performance. If folders contain a large number of messages, even ones just consisting of stubs, Outlook slows down a lot.
Microsoft therefore recommends that third-party email archiving solutions be configured to move email content completely out of the mailbox without retaining stub files in the mailbox. For more information, read this TechNet article. The information targets Exchange 2007, but it is also relevant for Exchange 2003 systems considering third-party email archiving.