The rise in e-mail archival is drawing attention to a feature of Microsoft® Exchange commonly referred to as ‘journaling’. If you search the Exchange Server 2003 Administration Guide, you will not find a single mention of the word ‘journaling’; so you may be wondering, what is this feature that everyone is talking about? In basic terms, journaling is the ability to record all communications in an organization. This includes e-mail, as well as other forms of communication, like fax, instant messaging, voice mail and others. Journaling is used by organizations in the financial services, insurance and healthcare industries to maintain records of communications that occur as employees conduct daily business. It records all e-mail communication sent and received, and feeds that into a larger journaling solution. Journaling is enabled at the Mailbox Store level and is enabled on the Store properties page. For journaling to function you must enter a mailbox where the journalized messages are sent; but before you run out and enable journaling on your Exchange Server, there are some important issues you should consider.

Prior to Exchange 2003, journaling existed in a single form. In Exchange 2003 SP 1 (also introduced in Exchange 2000 SP 3) a new form of journaling was introduced called ‘envelope journaling’. Original journaling is now referred to as ‘message-only’ journaling. Message-only journaling creates a copy of all messages to and from users on a mailbox database and sends the message copy to a specified journal mailbox. Message-only journaling does not account for blind carbon copy (Bcc) recipients, recipients from transport forwarding rules, or recipients from distribution group expansions.

Envelope journaling differs from message-only journaling because it permits you to archive information about the recipients who actually received the message, including Bcc recipients and recipients from distribution groups. In envelope journaling, all types of messages, except journal messages themselves, are journalized. This includes read receipts, meeting requests, out of office replies and delivery status notifications. Envelope journaling is suitable for most regulations that require e-mail archival for compliance and require a record about all recipients to whom a message is delivered. Message-only journaling does not journal data source names or read receipts and is not suitable for compliance.

Widespread journaling will have an impact on the performance of Exchange. If you are planning to enable journaling, you will have to deploy more hardware to maintain the current level of messaging service in your organization. When journaling is enabled, the server generates two messages: one for the recipients and one for the journal mailbox. You can estimate the impact of journaling on a mailbox database by assuming that the enabled Store can process approximately half of the messages being sent, as long as other conditions, such as CPU power, storage space, disk speed and bandwidth remain constant. You can expect 15 to 35 percent performance degradation. It is highly recommended that you house the journal mailbox on a dedicated server, separate from the regular Exchange servers.