Microsoft therefore needed to change its tactics
to provide a workable implementation of MRM. The change occurred in
Exchange 2010, and the same approach to messaging management is further
developed in Exchange 2013. Managed folders are deprecated in Exchange
2013. At this point, any remaining vestige of managed folders should be
eliminated from Exchange deployments as quickly as practicable.
MRM
depends on retention tags that are applied to items in mailboxes
through policy and are automatically processed thereafter by the MFA.
Retention tags can be applied to any item in any folder to specify what
action Exchange should take for the item when its retention period
expires. Supported actions include the hard (permanent) or soft
(recoverable) deletion of the item, moving the item to a personal
archive, or flagging the item for user attention. Retention policies
group retention tags together in a convenient manner so administrators
can apply policies to mailboxes rather than having to assign individual
retention tags to folders. Retention tags and policies are
organization-wide objects that are stored in Active Directory and can
therefore be applied to any mailbox in the organization after they are
created. Just as with Exchange 2007, the MFA is responsible for
checking mailbox contents against policy and taking whatever action is
determined by policy for items that exceed their retention period.
Table 1
describes the three types of retention tags Exchange 2010 and Exchange
2013 support. The type shown in the third column is a value passed to
the –Type parameter when you create a new tag with the
New-RetentionPolicyTag cmdlet. Exchange uses this value to understand
the scope of the items in a user mailbox to which it can apply the tag.
Table 1. Types of retention tags.
Tag type | Context | Target |
|---|
Retention policy tags (RPT) | Administrators
can apply these tags to default mailbox folders such as the Inbox, Sent
Items, and Deleted Items. If an RPT is assigned to a default folder,
all items in the folder automatically come under the control of the tag
unless the user applies a personal tag to the item. Only one RPT can be
assigned per default folder. | Supported for Exchange default mailbox folders such as the Inbox, Calendar, and Sent Items. See http://technet.microsoft.com/en-us/library/dd297955(v=exchg.150).aspx for an up-to-date list of supported folders. |
Default policy tags (DPT) | A
catch-all tag the MFA applies to any item that does not inherit a tag
from its parent folder or has not had a tag explicitly applied to it by
the user. In other words, if no other tag applies to an item, Exchange
will respect the instructions contained in the default tag. A retention
policy includes only a single DPT that is used to delete items; you can
include another DPT to control the movement of items into the archive.
It’s logical but sometimes overlooked that if you specify two DPTs in a
policy, the tag that moves items into the archive must have a shorter
retention period than the tag that deletes items. | Supported for any folder in a mailbox. |
Personal tags | Users
can apply these tags to nondefault folders and individual items in a
mailbox. Personal tags that move items into the archive can also be
applied to default folders. Personal tags mark an item with an explicit
retention, usually to comply with a business requirement. For example,
you might use an Audit tag to mark items that users are compelled to
retain for audit purposes. A retention policy can include many personal
tags. | Supported for any folder, item, or conversation in a mailbox. |
Microsoft
originally restricted the set of default folders to which you could
apply a retention policy tag to a smaller set including the Inbox, Sent
Items, and Deleted Items. The set has gradually expanded, and you can
now define a retention policy tag for just about every default folder,
including those such as the Calendar, Contacts, and Tasks, where
considerable care must be taken not to interfere with items that users
often want to retain for a considerable time. After all, no one will
thank you if you clean out the CEO’s calendar after 120 days!
The
set of default folders includes those that often accumulate debris
within mailboxes. Sync issues, Junk E-Mail, and RSS Feeds are
particularly interesting in this respect. It’s good to have these
folders cleaned out automatically because the items stored here aren’t
typically needed after a day or so.
When you create a new retention tag with EAC, you select the type of tag through a drop-down list (Figure 1).
The three values are:
Applied
automatically to entire mailbox This is a default policy tag (DPT). You
can have two of these in a policy, one for deleting items, the other
for archiving items. As pointed out in Table 2,
if you use two default tags, the default tag used to archive items must
have a shorter retention period than the tag that deletes them.
Exchange applies default tags to any untagged item in a mailbox.
Untagged items are those that do not inherit a tag based on the folder
in which they are stored or have not had a tag placed on them by a
user. Because of its influence over all untagged items in a mailbox,
the default tags are critical in terms of how long items remain in a
mailbox before they are deleted or archived.
Applied
automatically to a specific folder This refers to retention policy tags
(RPTs) that are associated with one of the supported default folders
such as the Inbox, Sent Items, and so on. You can have as many RPTs as
you like for a default folder, but only one RPT for a folder can be
included in a policy. EAC signals the error shown in Figure 2 if you attempt to add two RPTs for a default folder to a retention policy.
Applied
by users to items and folders (personal) As the name implies, these
tags are placed on folders or individual items as a result of users
making a personal decision that these contain information that needs to
be retained for some out-of-norm period. For instance, a folder
containing items required for financial audits might need to be
retained for six years and then deleted. Users could accomplish this
goal by placing a personal tag with a retention period of six years and
a retention action of DeleteAndAllowRecovery
on the folder that holds the items required for audit purposes. Other
items in the mailbox that are not in the folder can also be tagged with
the personal tag to retain them for six years.
Retention
tags cannot be applied to items directly. First, they have to be
assigned to a retention policy and the retention policy assigned, in
turn, to the mailboxes whose content you want to manage. A retention
tag can be reused several times in different policies. Although there
is no theoretical limit to the number of retention tags you can define
for an organization, it makes sense to create a set of tags that can be
shared and reused between retention policies rather than creating
separate tags for each policy.
Exchange can apply only one
retention policy tag and one archive tag to an item. Two simple rules
are enforced when Exchange evaluates policies that it can apply to an
item. The first rule states that the policy with the longest retention
period always wins and is intended to ensure that Exchange never
deletes an item before its time truly expires. The second rule is that
an explicit policy is always respected before an implicit or default
policy. If you apply a personal tag to an item to retain it for six
years and the default retention policy for the folder requires deletion
after 12 months, the item will be kept for six years. Personal tags can
be placed on items, conversations, or complete folders, and they are
transferred with items if you move them between folders.
Note
When
you apply a tag to a conversation, you really just apply the tag to the
items that make up the conversation at that point in time. Exchange
knows that the items are part of the conversation and can apply the
tag, but it won’t look for and tag new items as they arrive and join
the conversation. This is because a conversation is not a real storage
container within a mailbox and therefore cannot be permanently tagged.
In short, tags only exist in a persistent manner for folders and
individual items.
Of course, to make any sense of retention
policies, you also need to deploy clients that include the necessary
intelligence and user interface. The only clients in this category are
Outlook 2010, Outlook 2013, and Outlook Web App. At the time of
writing, no mobile client has any ability to display or set retention
tags (this situation might change with updates to the Outlook Web App
for Devices app). As you’ll see when you review how retention policies
function from a user perspective, the Outlook user interface provides
the richest views of retention policies and tags. Outlook Web App is
less capable but still highly usable.
