In-Place Archiving eliminates the need for Outlook personal store (.pst) files and allows users to store historical messages in an archive mailbox accessible in Microsoft Outlook 2010 and later and Microsoft Office Outlook Web App.
In Microsoft Exchange Server 2013, In-Place Archiving provides users with an alternate storage location in which to store historical messaging data. An In-Place Archive is an additional mailbox (called an archive mailbox) enabled for a mailbox user. Outlook 2007 and later and Outlook Web App users have seamless access to their archive mailbox. Using either of these client applications, users can view an archive mailbox and move or copy messages between their primary mailbox and the archive. In-Place Archiving presents a consistent view of messaging data to users and eliminates the user overhead required to manage .pst files.
You can provision a user’s archive on the same mailbox database as the user’s primary mailbox, another mailbox database on the same Mailbox server, or a mailbox database on another Mailbox server in the same Active Directory site. This provides flexibility to use tiered storage architecture and to store archive mailboxes on a different storage subsystem, such as near-line storage. In cross-premises Exchange 2010 and later deployments, you can also provision a cloud-based archive for mailboxes located on your on-premises Mailbox servers.