Applying a retention policy to control Exchange 2013 Health Mailboxes (or trying to, anyway)


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.

DisplayName                                   ItemCount

HealthMailbox79c03cca9b534959982a8773591c5f70      2416
HealthMailbox2c8bcd1322ac464d9529e82c577a876f      1251
HealthMailbox651e87104f764012aff75d0a7191464e        11
HealthMailbox79f3c6114b4a472cbd9e2cf207b179d1      2208
HealthMailboxbf5c4d3fa8a44999bf0e2e29fcb615d1      1069
HealthMailbox329cb4407fa84d01be0929879ad488d0      1349
HealthMailboxf4c968bbbbe6483faa7fc204f3634a09       752

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.

Health mailboxes show up where they really should not - in EAC

Health mailboxes show up where they really should not – in EAC

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 “15.0.0.0”. 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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About Tony Redmond

Exchange MVP, author, and rugby referee
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8 Responses to Applying a retention policy to control Exchange 2013 Health Mailboxes (or trying to, anyway)

  1. Pingback: Applying Retention Policies to Exchange 2013 Mailboxes « SME IT guy

  2. andreas M says:

    Good Posting. What I did was to create a Task which exports all the Searchmailbox mail to a normal user Mailbox called search once per day with search-mailbox -deletecontent.
    Then I applied the Retention policy to the search Mailbox.

  3. CamK says:

    have you heard anything back regarding this bug? i am in the same boat. Thanks!

    • No, but I don’t know if the developers think that it is a bug. What’s for sure is that Exchange 2013 CU1 generates a lot less traffic to these health mailboxes so the problem is lessened. I expect that further improvement will come in CU2 as the word (from TechEd North America) is that the developers have been looking at how Managed Availability works in production to tweak it a tad more.

      TR

  4. Mike DiVergilio says:

    Tony, I thought I would ask the question again now that we are on CU3? Any change to the behavior once you place a retention policy in these mailboxes?

  5. Hi Tony,
    Any changes w.r.t to SP1 since health mailbox holding lot of items in it. Will it be best practice to clean the email item which are older than 30 days…will have any impact

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