Exchange 2013 Monitoring Mailboxes

Exchange Server 2013 introduced a new feature called Managed Availability, which is a built-in monitoring system with self-recovery capabilities. Managed Availability performs continuous tests (probes) that simulate end-user actions, to detect possible problems with Exchange components or their dependencies. If probes are failing, it performs simple recovery actions to bring the affected component in healthy state. It uses special type of mailboxes, called Monitoring Mailboxes or health mailboxes, to simulate end-user kinds of tests.Functioning of Managed Availability is implemented by Microsoft Exchange Health Manager Service running on each Exchange Server 2013 role.

Monitoring Mailboxes

MS Exchange Health Manager Service is responsible for creating and managing monitoring mailboxes. The MS Exchange Health Manager Service runs in two processes, MSExchangeHMHost.exe and MSExchangeHMWorker.exe.

HM worker process, at the time of startup, checks for availability of monitoring mailboxes and creates monitoring mailboxes as needed.

monitoring mailboxes are created under following container in the domain Exchange server resides:

<ADdomain>\Microsoft Exchange System Objects\Monitoring Mailboxes

Logic used to create Monitoring/Health mailboxes

Logic is depends on the CU, Exchange role and mailbox database present.

Logic used for 2013 servers between RTM to CU5:

    • One monitoring mailbox per mailbox database copy, plus one for each CAS servers.

[PS] C:\>Get-Mailbox -Monitoring | ft displayname,whencreated
DisplayName                                         WhenCreated
-----------                                         -----------
HealthMailboxb285a119be6649b3a89574f078e947f5      11/10/2014 9:07:29 AM
HealthMailbox60d8a8d1285e41bfa5ce1ef1fb93d14e      11/10/2014 9:07:36 AM

The display name of the monitoring mailbox created for database copy contained the GUID of the mailbox database for which it was created and GUID of the CAS server.

Logic used for 2013 servers from CU6 onwards:

    • One monitoring mailbox for each mailbox database copy and 10 monitoring mailboxes for each CAS server

Naming Conversion for the monitoring mailboxes create for databases

“HealthMailbox-“ + host name of server + “-“ + database name

Note - if you rename DB1 to DB2, HM worker will create new monitoring mailbox for DB2 on next startup.

Naming Conversion for the monitoring mailboxes create for CAS servers

“HealthMailbox-“ + host name of the CAS server + “-001” through “010.”

Note - 10 monitoring mailboxes will be distribute among the databases, if we have multiple.

How to re-create monitoring mailboxes

Mailbox database cleanup will not remove the AD objects associated with the monitoring mailboxes. So it may create some orphaned AD objects. In this case we may have to remove all existing monitoring mailboxes and clean all AD objects associated with the monitoring mailboxes including orphaned AD objects.

1. Stop the “Microsoft Exchange Server Health Manager” service on all Exchange Server 2013 servers.
2. Get-Mailbox -Monitoring | Disable-Mailbox
3. Delete the health mailbox user accounts.
4. Wait for AD replication or force AD replication.
5. Start the “Microsoft Exchange Server Health Manager” on all Exchange Server 2013 servers. 

General Notes

1. HM worker process will manage the monitoring mailboxes passwords.
2. Do not apply policies to the monitoring mailboxes user accounts.
3. Since HM worker handles password resets for monitoring mailboxes, in a large environment, it is normal to see increased password reset traffic for monitoring mailbox accounts.
4. Do not move monitoring mailboxes between mailbox databases.
5. Do not apply mailbox quotas or retention policies to monitoring mailboxes.