When you configure a journaling mailbox to accept journal reports, you must determine the maximum size of the journaling mailbox. As with any other mailbox, the maximum size depends on the data to be stored in the mailbox, the hardware resources available, and the disaster recovery requirements for the server where the journaling mailbox is located. In addition to these considerations, you must also consider what will occur if a journaling mailbox exceeds the configured mailbox quota.

When you configure the Prohibit send and receive at (KB) option for a storage quota on a journaling mailbox, the mailbox accepts journal reports until it reaches the configured storage quota. When the prohibit send and receive storage quota is exceeded, the journaling mailbox stops accepting journal reports.

Exchange doesn't return journal reports to the original sender as it does with regular messages. Instead, it holds undelivered journal reports in a mail queue and tries to redeliver them until delivery is successful. Although this enables Exchange to eventually deliver all the journal reports generated, it can be problematic in organizations with high messaging traffic because the mail queues on the affected Hub Transport servers can grow quickly.

To reduce the possibility that your journaling mailbox will reject journal reports because it has reached the configured storage quota, we recommend that you configure its prohibit send and receive storage quota to the maximum size that your hardware resources and disaster recovery capabilities allow for.

Important:
If you configure journaling mailboxes without storage quotas, monitor the Mailbox server to ensure that it doesn't exceed the available hardware resources or disaster recovery capabilities.

If you must configure a prohibit send and receive storage quota on a journaling mailbox and expect that the configured storage quota might be exceeded, you can configure an alternate journaling mailbox. For more information about alternate journaling mailboxes, see "Alternate Journaling Mailbox" later in this topic. When a journal report is rejected by a journaling mailbox, Event ID 8010 is logged in the Application event log. By monitoring the Application event log for this event, you can be alerted to a potential problem with the journaling mailbox and resolve the situation quickly.

For information about how to configure storage quotas on a journaling mailbox, see Configure Storage Quotas for a Mailbox.

When the journaling mailbox is unavailable, you may not want rejected journal reports to collect in an e-mail queue on Hub Transport servers. Instead, you can configure an alternate journaling mailbox to store those journal reports. The alternate journaling mailbox receives the journal reports as attachments in the non-delivery reports (NDRs) generated when the journaling mailbox or the server on which it's located refuses delivery of the journal report or becomes unavailable.

When the journaling mailbox becomes available again, you can use the Send Again feature of Microsoft Office Outlook to submit journal reports for delivery to the journaling mailbox.

Different mailbox databases and journal rules may be configured to deliver journal reports to different journaling mailboxes. However, when you configure an alternate journaling mailbox, all the journal reports that are rejected or can't be delivered across your entire Exchange 2010 organization are delivered to the alternate journaling mailbox. Therefore, it's important to make sure that the alternate journaling mailbox and the Mailbox server where it's located can support many journal reports.

Caution:
If you configure an alternate journaling mailbox, you must monitor the mailbox to make sure that it doesn't become unavailable. If the alternate journaling mailbox also becomes unavailable or rejects journal reports at the same time, the rejected journal reports are lost and can't be retrieved. This is an important factor when considering whether to use an alternate journaling mailbox.

After an alternate journaling mailbox is configured, only journal reports submitted for delivery to any unavailable journaling mailbox are redirected to it. Journal reports that have already failed delivery before the alternate journaling mailbox is configured aren't redirected.

If you configure an alternate journaling mailbox, you can reduce the load on your Hub Transport servers and Mailbox servers. Exchange doesn't continually try to deliver the journal reports to an unavailable journaling mailbox. Instead, Exchange redirects them to the alternate journaling mailbox where they can remain until you're ready to resubmit them to the journaling mailbox.

However, because the alternate journaling mailbox collects all the rejected journal reports for the entire Exchange 2010 organization, you must make sure that this doesn't violate any laws or regulations that apply to your organization. If laws or regulations prohibit your organization from allowing journal reports sent to different journaling mailboxes from being stored in the same alternate journaling mailbox, you may be unable to configure an alternate journaling mailbox. Discuss this with your legal representatives to determine whether you can use an alternate journaling mailbox.

When you configure an alternate journaling mailbox, you should use the same criteria that you used when you configured the journaling mailbox. You must make sure that the following conditions are true:

• Authorized submission   Only authorized accounts should be able to submit journal reports.
  
  
• Authorized access   Only those individuals who are authorized to access the mailbox are given access to the mailbox.
  
  
• Adequate storage quota   Configure a storage quota that meets the needs of your data, hardware, and disaster recovery needs.
  
  

Remember that because the alternate journaling mailbox accepts rejected journal reports for all journaling mailboxes in your Exchange 2010 organization, the hardware resource requirements and mailbox storage quotas may be significantly larger than those required for a journaling mailbox.

For more information about how to configure an alternate journaling mailbox, see Configure or Remove an Alternate Journaling Mailbox.