In Exchange Server 2010, Microsoft has deprecated “Managed Folders” and replaced those with “Retention Policies”. Unfortunately, at Release-To-Manufacturing (RTM, that is – when Exchange Server 2010 originally shipped), you cannot control Retention Policies via the Exchange Management Console (in other words, while using a GUI tool) and when attempting to control Retention Policies via the Exchange Management Shell (that is, while using a CLI – command-line interface) you could not specify specific policies for specific message types (this was a bug in the RTM version of Exchange Server 2010 and has since been corrected). Service Pack 1 for Exchange Server 2010 will allow the Exchange administrator to create, delete, and modify Retention Policies (and their associated Retention Tags) from within the Exchange Management Console.
In the initial release of Exchange Server 2010, Exchange has a default retention policy which causes all messages older than one year to be moved to the archive mailbox. This does require, of course, that a user have an archive mailbox.
If the user has not been assigned an archive mailbox, then this policy has no effect.
In Exchange Server 2007, Retention Policies required that the Managed Folder Assistant (MFA) be scheduled to run on a regular basis (by default, the MFA was set to “never run” and once you enabled it [without changing the default schedule], it ran between 1am and 8am each day).
However, if the user has been assigned an archive mailbox in Exchange Server 2010, then this policy can come as some surprise. In order to view any archived items (that is, emails, calendar entries, tasks, journal items, etc.) that are more than a year old, the user must use either Outlook Web App (OWA) 2010 or Office Outlook 2010. Outlook 2007 does not currently provide visibility to the archive mailbox (Microsoft has promised an update that will provide this functionality).
In Exchange Server 2010, the MFA is not required to process Retention Policies and their associated tags. This is handled by the normal marking processes within Exchange Server.
In Outlook 2010 or OWA 2010, by default the archive mailbox will be named “Online Archive - <mailbox name>”. For example, if the mailbox is named “Michael B. Smith”, then the archive mailbox will be named “Online Archive – Michael B. Smith”.
Within the archive mailbox, Exchange will automatically create the complete folder structure that was present in the user’s primary mailbox. For example, if the user had a folder structure named “Company\Intel\Incoming”, and “Company” was a folder at the root of the user’s mailbox, and there were messages older than one year within the “Incoming” folder, then Exchange would’ve automatically moved those messages to the “Company\Intel\Incoming” folder structure within the archive mailbox. The folder structure is not created within the archive mailbox until messages need to be moved into a given folder from the primary mailbox to the archive mailbox.
Within the archive mailbox, you (that is, the Exchange administrator) can specify different quotas for the archive mailbox than those that apply to the primary mailbox (this must be done using the EMS Set-Mailbox cmdlet with the ArchiveQuota and ArchiveWarningQuota parameters - it cannot currently be done using the EMC).
The archive folder is indexed by the normal Exchange Search processes and if you execute a search from within OWA 2010 or Outlook 2010, you will see the results of those searches – including the contents of the archive mailbox.
Finally, it is worthwhile to note that Microsoft is suggesting that a user’s primary mailbox plus a user’s archive mailbox should be used to replace any use of PSTs for that user within a given company (and Microsoft has completely removed the storage limits on mailbox databases that used to exist in Exchange Standard Edition). Arguably, this isn’t practical in the RTM version of Exchange Server 2010, but in Service Pack 1 the Exchange administrator can place archive mailboxes in different mailbox databases than the primary mailbox. This can allow for reductions in cost for archive mailboxes (when compared to per-user storage for PSTs) compared to primary mailboxes.