From an administrator perspective, e-mail archiving is the practice of removing stale content from the primary message database(s) on an e-mail server to a secondary storage area. This helps maintain e-mail server performance levels on current content while retaining access to messages that are only referenced sparingly. Historically, going back ten years or more, archiving was often the responsibility of individual users, but recently the reasons for archiving have evolved and central management is critical in some industries.
Archiving does not mean inaccessible. E-mail archives only represent an alternate storage, not a final backup. Centrally managed archives should be available to users if they need to query older content and also to meet relevant regulatory compliance agencies. Archives should be indexed to provide efficient retrieval of messages, attachments and other content by authorized individuals or agencies.
Archives may be completely disassociated with the primary messaging system or they may be integrated. Message stubs may be left in the users' mailboxes so when users access that content, it is just pulled from the archive source for viewing rather than the primary mail server. Alternatively, the archive solution may require a separate logon, often through a web interface, to access content prior to a certain point in time.
Whatever the reason, or the mechanism, e-mail archiving has proven to be necessary in mature enterprises that depend on robust messaging solutions for their ongoing business demands.