Exchange archiving plans specify which messages are archived, how long they are retained, and which messages are content indexed.
From the navigation pane, go to Manage > Plans.
The Plans page appears.
In the upper-right area of the page, expand Create plan, and then select Exchange mailbox.
The Select an exchange mailbox plan page appears.
Click the Exchange archiving plan link.
In the Plan name box, enter a name for the plan.
To enable archiving on the mailbox, move the Enable backup on archived mailbox toggle key to the right.
Under Retention settings, specify how long to retain messages:
To retain messages for an unlimited time, select Retain messages indefinitely.
To retain messages for a limited number of days based on the message received time, select Retain messages based on Received Time for, and then enter the number of days to retain the messages.
To retain messages for a limited number of days based on the message deletion time, select Retain messages based on Deletion Time for, and then enter the number of days to retain the messages.
To define cleanup rules, under Cleanup settings, do the following:
Move the Custom cleanup settings toggle key to the right.
In the Clean up messages older than box, enter the number of days after the received time that you want to clean up messages.
In the Clean up messages larger than box, enter the size, in kilobytes, of messages that you want to clean up.
Note: For messages to be cleaned up, both the Clean up messages older than value and Clean up messages larger than value must be met.
Under Search settings, specify the types of data to include in searches:
Include the bodies of emails and attachments
Search for email messages by exact keyword matching
See previews of email messages while browsing
Include personally identifiable information (PII), such as Social Security Numbers and credit card numbers