Understanding the Mailbox Move Request in Exchange 2010

Mailbox Move Request is the process of moving a mailbox from its source mailbox database to a target mailbox database. Target mailbox database can be either on the same server or on a different server or even in a different domain/forest.  Mailboxes are moved for various reasons like transitioning to the new environment or investigating an issue or corruption in the mailbox or user physical local changes, company acquisition and mergers, etc.

Exchange 2010 Mailbox Move Request is processed by two services running on the Exchange 2010 Client Access Server:

  • Microsoft Exchange Mailbox Replication Service (MRS)
  • Microsoft Exchange Mailbox Replication Proxy (MRSProxy) Service

Microsoft Exchange Mailbox Replication Service (MRS)

MRS processes the move process and performs asynchronous online move. In this process the end user can still access his/her email account during the move. The mailbox gets locked-out only at the end of the process for the brief period of time when final synchronization is performed between the source and destination.

Microsoft Exchange Mailbox Replication Proxy (MRSProxy) Service

MRSProxy service is disabled by default and it needs to be turned on when cross-forest mailbox move request is performed. This service helps to facilitate the cross-forest move request and it needs to be running on remote/target forest where the mailbox has been moved to.

Basically there are two types of Move Requests:

  • New Local Move request
  • New Remote Move Request

New Local Move Request

It is the process of moving the mailbox from one database to other within the same site or different Active Directory site and within the same Exchange organization. In this process MRS plays a major role in moving the mailbox from source to target database.

  1. When a new move request command is executed, it updates Active Directory and then places a message in the system mailbox within the Active Directory site where the move request was initiated and marks the move request status as Queued.
  2. All MRS instances periodically check the system mailbox in every Active Directory site and verify if there is any move request queued.
  3. MRS initiates the move of data from source to the target database and marks the move status as “In Progress”.
  4. Once the move is completed, new mailbox at the target database is activated and move request is marked as “Completion in Progress”. Until this point, users will be able to access their email without any distraction. During this final mailbox synchronization phase, source mailbox is locked only for a short duration.
  5. Once the synchronization is completed, mailbox at the target database is activated and the old mailbox at source is soft deleted. Finally, the move request status is marked as “Completed”.
  6. Once the migration is completed, the user needs to close and re-open Outlook or log off and login back to allow Outlook to connect the mailbox from the new database.

New Remote Move Request

Remote mailbox move request is the process of moving mailbox from one forest to the other forest or performing cross-forest migration.

It can further be divided into two scenarios:

  • Remote Move Request where both source and target forest are in Exchange 2010.
  • Remote Move Request where target forest is in Exchange 2010 and the source is the legacy forest with Exchange 2003 SP2, Exchange 2007 SP3, or a combination of both, and no Exchange 2010 Client Access server is installed.

You could make use of “Prepare-MoveRequest.ps1” script to prepare the target forest Mail Enabled User (MEU) to perform cross-forest migration.

Remote move request with source and target forest on Exchange 2010

In this scenario we have one forest in Exchange 2010, and the other forest has the latest Exchange 2010 client Access Server, and MRS and MRSProxy is started on all the Client Access Servers.

  1. When a New-Moverequest cmdlet is executed in the target forest, MRS at the source target initiates the move request. The cmdlet updates the Active Directory and places a message in the system mailbox within the Active Directory site where the move request was initiated and marks the move request status as Queued.
  2.  MRS at the target forest communicates with the MRS proxy at the source forest and  pulls mailbox data from the mailbox server through the MRSProxy server in the target forest Mail Enabled User.
  3. When the mailbox move is complete, MRSProxy locks the source mailbox for a short period of time to perform the final synchronization. During this period, the status changes to “Completion In Progress”.
  4. Finally, MRS converts the source mailbox to MEU and in the target forest, MRSProxy converts the MEU to the mailbox, then the status is marked as completed.
  5. Once the migration is completed, the user needs to close and re-open Outlook or log off and login back to allow Outlook to connect the mailbox from the new database.

Remote Move Request where target forest is in Exchange 2010 and the source is the legacy forest

In this scenario, where you have source forest in Exchange 2007 or Exchange 2003, and it does not contain an Exchange 2010 Client Access Server to run MRSProxy and target forest in Exchange 2010.

  1. Moving mailboxes from Exchange 2003 to Exchange 2010, the mailbox move will go offline and user will not be able to access their mailbox during the move. Move from Exchange 2007 SP3 to Exchange 2010 will be online, and the users can continue accessing their mailboxes during the move.
  2. When a New-Moverequest cmdlet is executed in the target forest, MRS at the source target initiates the move request. The cmdlet updates the Active Directory and places a message in the system mailbox within the Active Directory site where the move request is initiated and marks the status as Queued.
  3. MRS in the Exchange 2010 forest will directly access the remote legacy database and the remote organization’s Active Directory server.
  4. When the mailbox move is complete, the source mailbox is locked for the short period of time to perform the final synchronization. During this period, the status changes to “Completion in Progress”.
  5. Finally, MRS converts the source mailbox to MEU and in the target forest MEU is converted to Mailbox, then finally status is marked as “Completed”.

Make sure Autodiscover is configured at the target forest, so the Outlook client from the target forest is able to resolve the source forest mailbox. Once the autodiscover is configured, users just need to close and re-open Outlook or just log off and login back to continue to access their email from the new Exchange server. To avoid any performance impact on the production Client Access server, you can stop MRS on the production server and have some migration servers only running MRS Service.

I hope you got a fair understanding on different move requests, how it works internally, and how to make it work in real time mode.