If an Exchange 2010 organization is involved in the mailbox migration process, consider that in Exchange 2010 all mailbox communications flow via Client Access Servers (CAS) instead of Mailbox Servers as in previous versions of Exchange. Therefore Migration Manager for Exchange agents use CAS for mailbox and calendar processing.
When migrating mailboxes to Exchange Server 2013/2016/2019, consider the following:
- Migration Agent for Exchange cannot process a message that is larger than 40MB. This limit is set in Migration Manager for Exchange configuration project to ensure migration stability. If you have strong reasons to change that value, see the SizeLimitInMbPerBatchUploadToO365 and SizeLimitInMbPerBatchUploadToExchange parameters in Configuring Migration Using PowerShell
- If you want to change an agent instance for a collection that is being processed, you should stop the agent, wait until the current session is finished and then specify the agent instance you need.
- If a mailbox is added to more than one collection via groups or organizational units, the Migration Agent for Exchange processes this mailbox only for the collection that is the first in the synchronization order.
- One instance of Migration Agent for Exchange cannot process collections from on-premise Exchange migration and Microsoft Office 365 migration projects at the same time.
- If a mailbox move request completes with an error, delete this request before the agent creates a new one.
Mailbox migration to the target environment is transparent. It is recommended to start mailbox migration after the domain and directory migration is completed and after the public folder data is copied to the target environment.
Calendar and free/busy synchronization should be started simultaneously with mailbox migration to enable users to work without interruption during the coexistence period.
NOTE: The scenario involving migrating users from Active Directory to Microsoft Office 365 and their mailboxes from the on-premises Exchange organization to Microsoft Exchange Online is described separately in the Migrating To Microsoft Office 365 document included in the Migration Manager documentation set.
To begin mailbox migration, right-click the Mailbox Synchronization node in the management tree and click Add Mailbox Synchronization Job. This opens a dialog box that lets you select one of the following methods to synchronize mailboxes:
- Mailbox synchronization job
- Office 365 Mailbox Migration Job
- Native Move Job
- Legacy Mailbox Synchronization Job
The guidelines for choosing the right type of job are in the Mailbox Migration Process topic.
NOTE: Office 365 mailbox migration is described in the dedicated Migrating to Microsoft Office 365 document.
You can track the mailbox migration progress using the Statistics dashboard. For information on how to do that, see Tracking the Migration Progress.
A mailbox synchronization job is currently the only method for migrating mailboxes to Microsoft Exchange 2010 (only for migration from Exchange 2010 or later by MAgE), Exchange 2013 or higher.
Step 1. Select the Source Exchange Organization
Specify the source organization where the mailboxes need to be synchronized and the credentials to use for performing the synchronization operations. You can specify a single set of credentials for working with both Active Directory and Exchange, or two distinct sets of credentials.
Step 2. Select the Target Exchange Organization
Specify the target Exchange organization where the mailboxes need to be synchronized and the credentials to use for performing the synchronization operations. You can specify a single set of credentials for working with both Active Directory and Exchange, or two distinct sets of credentials.
Step 3. Configure the Notification Message
Specify the notification messages that will be sent to the old and new mailboxes involved in the migration. Use the default notification messages or customize them as necessary.
Step 4. Set Up Migration Agent for Exchange
The Migration Agent for Exchange is used for performing direct mailbox synchronization operations. This step lets you set up the agent on an agent host that you select.
The default installation path is in the hierarchy of the Program Files system folder. You can customize the path, but your custom path will be used only if there are no previously installed instances of the Migration Agent for Exchange on the computer. Otherwise, the agent will be installed to the same location as the other existing instances regardless of the path you specify.
You can also override the default credentials that the agent will use. However, note that in this case you will be changing the credentials not only for the agent instance you are installing, but also for any existing agent instances on the agent host.
Reconfiguring Mailbox Synchronization Jobs
To change the original settings you specified during mailbox synchronization job creation, open the properties of the job.