Plan to migrate Exchange mailboxes to Exchange Online
Topic Last Modified: 2014-02-27
Summary: Describes planning options for migrating on-premises Exchange to Office 365.
If your organization is using Exchange Server 2013, Exchange Server 2010, Exchange Server 2007, Exchange Server 2003, or Hosted Exchange, you have several ways to migrate mailbox data. Exchange Server migration methods are described in the following table.
For information on migrating on-premises email to Exchange Online in Office 365, see Exchange Online Migration Performance and Best Practices.
Types of Exchange Server migrations
Tools and methods
Cutover Exchange migration
Intended for small organizations that want a quick cutover, with no coexistence, from their existing Exchange mail environments to Exchange Online. All on-premises mailboxes are migrated in preparation for moving your entire email organization to Exchange Online. You can migrate a maximum of 2,000 mailboxes from your on-premises Exchange organization to Exchange Online.
User identities are automatically provisioned by the tool. After cutover, single sign-on can be deployed.
Email migration tool via Exchange Administration Center (EAC). You can also use the Exchange Management Shell.
For step-by-step instructions, see Migrate All Mailboxes to Exchange Online with a Cutover Migration.
Staged Exchange migration
Intended for organizations that want a shorter period of coexistence from their existing Exchange mail environments to Exchange Online. User identities are automatically provisioned by the Azure Active Directory Sync tool. After all users are migrated to Exchange Online, single sign-on can be deployed.
This type of migration lets you maintain coexistence between your on-premises and Office 365 email organizations. In this scenario, you can move some mailboxes to Exchange Online while maintaining the rest of the mailboxes in your on-premises mail environment.
Email migration tool via Exchange Administration Center (EAC) or the Exchange Management Shell and a CSV file; Azure Active Directory Sync tool to keep your on-premises Active Directory synchronized with Office 365 and Exchange Online.
For step-by-step instructions, see Migrate Mailboxes to Exchange Online with a Staged Exchange Migration.
Note: On-premises Exchange decommissioning after a staged migration should be planned carefully with the help of an Office 365 deployment specialist. Contact Office 365 support for more information.
Hybrid deployment migration
This type of migration lets on-premises users see calendar or free/busy information for Exchange Online users. You must add a hybrid server to your on-premises Exchange environment.
Install and configure the server running Exchange Server 2013 or 2010.
Use the Azure Active Directory Sync tool to keep your on-premises Active Directory synchronized with Office 365 and Exchange Online.
For step-by-step instructions, use the Exchange Server Deployment Assistant.
|The migration velocity, especially if any third-party tools are involved, might be affected by the Exchange Web Services (EWS) and MAPI limits for Exchange Online. For more information, see the Exchange Online Migration Performance Guide.|