I thought I would take a better look at the new Exchange 2010 feature, the personal Archive which is effectively a second mailbox for a user. The personal Archive was introduced to Exchange server to give administrators an option for dealing with .pst files which traditionally have the following problems:

1. Access to .pst files sitting on file shares are not supported.
2. .pst files generally reside on workstations and as such are a problem to locate and search through for discovery requests.
3. .pst files are prone to corruption.

In addition to the personal archive feature of Exchange server 2010, Microsoft have introduced retention and MoveToArchive policies which will enable administrators and users to control mailboxes sizes.

With the release of Exchange Server 2010 RTM the personal archive mailbox had to be created in the same mailbox database as the users mailbox but with the advent of Exchange Server 2010 SP1 it is now possible to store the personal archive mailbox in a different mailbox database which could be on a completely separate server. The one thing to note here however is that the personal archive feature of Exchange 2010 does not utilize any single instance storage so it is not as efficient as Quest Archive Manager or Symantec Enterprise Vault which can cut your overall storage costs. Also similar to a full user mailbox there is a quota which can be managed by administrators’ for the personal archive mailboxes.

When looking to archive-enable an existing mailbox the administrator is presented with an option to specify a specific database in which to create an archive. In this example I have a mailbox database to host the live user mailboxes and a separate mailbox database to host their archives on a second server.

The Exchange Server 2010 Archive cannot work with emails captured through the Journal process in Exchange. In the absence of a 3rd party product which normally captures Journaled content you are a limited to storing Journal mail in a dedicated mailbox which may or may not be managed by Exchange Server native functionality to keep it’s size under control.

The personal archive can have quota’s set in order to control size and disk usage by the archive. The default values for the archive vary between the RTM and SP1 versions of Exchange Server 2010

If enabling the archive for a new or existing user, the archive folder will be visible in Outlook 2010 and OWA 2010 straight away, however the retention policies will not be available to the user until the managed folder assistant has run which by default occurs overnight. However it is possible to force the issue by running the following command

Start-ManagedFolderAssistant –identity <MailboxID>

After running this command a user will have to logout of OWA or Outlook before the retention policies will be available.

The Exchange archive folder is only visible to users of Microsoft Office Outlook 2010 and Outlook Web App 2010 although Microsoft are looking to release an update for Outlook 2007 possibly in the first half of 2011 to add support. The Exchange archive folder however is not available to Outlook 2010 while working offline.

To assist administrators manage mailbox content Exchange server includes retention policies which can be applied to mailboxes. Retention policies are replacing managed folders which are de-emphasised from Exchange server 2007.

Retention policies consist of a number of Retention Policy Tags which with the advent of Exchange Server 2010 SP1 can be created and edited through the Management Console, and there are three types of policy Tag.

Default Policy Tag – These tags when added to a Retention Policy apply at the mailbox root and apply to all items in a mailbox unless overridden by a more specific folder level policy. There can be only one Default Policy Tag per retention policy which can include one of the available actions which are Delete and allow Recovery, Permanently Delete and Move to Archive..

Retention Policy Tag -  These tags can apply retention to a default mailbox folders such as inbox and can include actions such as Delete and allow Recovery and Permanently Delete. A Retention Policy Tag cannot include the action Move to Archive. As a result the only way of applying a Move to Archive action on a default folder would be via the Default Policy Tag. When applied to a default folder a Retention Policy Tag cannot be overridden by a User, however a user can set a Personal Tag on individual items within a default folder.

Personal Tag – These tags are ones that can be applied by a user and can include all of the available actions. However the user is not able to apply a personal tag to a default mailbox folder but can apply the tag to items within a default folder. Of course Personal Tags can be applied to the users custom folders. Personal Tags that include the Delete and Allow Recovery and Permanently Delete options appear under the Retention Policies menu options in Outlook and OWA where as Personal Tags with the Move to Archive option appear under the Archive Policy menu options. If a Personal Tag is applied it will always be processed in preference to Retention Policy Tags or Default Policy Tags even if it means that the message will be moved or deleted sooner or later than the settings specified in the Retention Policy Tag or the Default Policy Tag.

Unfortunately the retention policies are indiscriminate and cannot be applied by keywords in the message subject or body.

Retention policies should be planned to meet the companies retention in advance of deployment as it is best practice to keep the set of Retention Policy Tags and Retention Policies to a minimum and kept simple. From time to time however some Retention Policy Tags will fall out of use but there are some considerations that need to be accounted for:

1. Removing a Retention Policy Tag from a Retention Policy makes it unavailable to users but items that are stamped with that tag are still processed by the Managed Folder Assistant with the properties of that tag.
2. Deleting a Retention Policy Tag will remove the Tag from all items with that tag applied. This should be done with caution as this has the potential to generate a high workload for the Managed Folder Assistant which will consume server resources depending on the number of mailboxes and items affected by the tag removal.

The implementation of Archiving and Retention Policies is somewhat unique compared to the 3rd party offerings in the marketplace. Before taking the decision to implement Exchange Archiving to meet your compliance needs I would advise checking that the available functionality meets whatever local standards you need to work to. Features such as users being able to modify policies on specific items may exclude the solution from standing up in a court of law if required.