Reading Jeff Guillet’s ExBPA blog the other day, I came across an entry describing a solution for the problem posed by Exchange 2013’s health mailboxes when journaling. The health mailboxes are new in Exchange 2013 and are used by the Managed Availability system to send probes to different Exchange components to ensure that they are in robust good health. Two health mailboxes are created per mailbox database so a server that supports a number of databases will generate a reasonable number of probe messages, all of which accumulate and have to be journaled, if you elect to capture messages via journaling for archive or retention purposes.
In any case, I rather liked the solution described by Jeff, which is to create a journal rule based on a dynamic distribution group with the health mailboxes being excluded from the group by filtering on a value in one of Exchange’s custom attributes. I might change the command used to create the group with the New-DynamicDistributionGroup cmdlet by including a value for –RecipientContainer to ensure that the OPATH filter picks up all mailboxes in the organization, but that’s just being picky.
The solution stops the messages created by health mailboxes from being journaled, but does nothing to stop the messages accumulating in the mailboxes. Thus, you might end up seeing something like this when running the Get-MailboxStatistics cmdlet to examine how many items are in the health mailboxes.
Seeing that I am in the middle of writing the chapter on compliance for “Exchange 2013 Inside Out” The bright idea then came into my mind that it should be possible to apply a retention policy to these mailboxes to have the Managed Folder Assistant clean them out on a regular basis. In fact, a single-tag policy will do the trick, as all we really need is a default tag that removes items after a set period, which should be pretty short as there’s no good reason to retain anything in these mailboxes. I therefore created a default tag that would permanently delete items older than 2 days and added it to a new retention policy that I called “Health Mailboxes Retention Policy” (insightful naming conventions have never come easily to me).
I then applied the new retention policy to the health mailboxes by running the following command:
Get-Mailbox –Monitoring | Set-Mailbox –RetentionPolicy ‘Health Mailboxes Retention Policy’
Running Get-Mailbox with the –Monitoring switch returns a list of all of the mailboxes marked as being used by Exchange for monitoring purposes. It’s an easy way of identifying the health mailboxes within the organization. However, when I ran the command again to see whether the retention policy was now in place, no mailboxes showed up. This was very odd because the mailboxes and their underlying Active Directory user objects were still in place and were still operational as probes were still being sent and could be identified by running the Get-MessageTrackingLog cmdlet.
Even odder, I could now see the health mailboxes in the Exchange Administration Center (EAC) where they had been invisible beforehand. A little investigation revealed that Exchange now regarded the health mailboxes to be “user mailboxes”, evident by the fact that their RecipientTypeDetails properties were reported to be “UserMailbox” rather than “MonitoringMailbox”. Further probing revealed that although the health mailboxes are exposed through EAC, you can’t update their properties as the objects can only be managed by a console with a version higher than “18.104.22.168”. I had assumed that EAC was in this category because its version is 15.0.32, the RTM version for Exchange 2013, but something else is clearly getting in the way. I also haven’t figured out how to reset the RecipientTypeDetails property for the health mailboxes as the Set-Mailbox cmdlet doesn’t support this property.
I’ve reported this issue as a bug to Microsoft and no doubt will hear back from their support staff soon. In the interim, the good thing is that the retention policy is working as planned and MFA is clearing out items once they are more than 2 days old.
New health mailboxes are created normally with new mailbox databases. These mailboxes operate just like their older counterparts. However, I won’t apply the retention policy to these mailboxes until I hear back from Microsoft support! Living on the edge with the new stuff in Exchange 2013 can sometimes get on the nerves…
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