Exchange Online Migration Methods

In this article, you will learn about the migration methods of Exchange Online.

Exchange Online Migration

 
Exchange On-Premises to Exchange Online Migration
  1. Cutover migration
  2. Staged migration
  3. Hybrid migration
  4. Minimal Hybrid
Exchange Online to Exchange Online Migration (Tenant to Tenant)
  1. PST Migration
  2. 3rd Party Tool
Other Email Services to Exchange Online Migration
  1. IMAP migration
  2. Gsuite to Office 365 Migration (inbuilt Tool)
  3. 3rd Party Tool
  4. PST migration

Exchange On-Premises to Exchange Online Migration

 
Cutover Migration
 
This migration type is suitable for the below scenario.
  • Your current on-premises Exchange organization is Microsoft Exchange Server 2003 or later.
  • Your on-premises Exchange organization has fewer than 2,000 mailboxes.
  • The primary domain name used for your on-premises Exchange organization must be an accepted as a domain owned by you in your Office 365 organization.
Prepare
  • Configure Outlook Anywhere on your on-premises Exchange Server
  • A Public Certificate issued by Trusted CA.
  • Verify that you can connect to your Exchange organization using Outlook Anywhere.
  • Delegate permissions of All mailbox to Admin Account.
  • Disable Unified Messaging (UM)
  • Create security groups and clean up delegates
Migrate
  • Add & Verify Domain in Office 365
  • Connect Office 365 with On-Premises email Services.
  • Create & Start Migration Batches
  • Email Routing
  • Clear Migration batches
  • Assign licenses to Office 365 users.
Reference
https://docs.microsoft.com/en-us/exchange/mailbox-migration/mailbox-migration
 
Staged Migration
 
This migration type is suitable for the below scenario.
  • You can migrate the contents of user mailboxes from an Exchange 2003 or Exchange 2007 email to Office 365 over time by using a staged migration.
Prepare
  • Configure Outlook Anywhere on your on-premises Exchange Server
  • Verify that you can connect to your Exchange organization using Outlook Anywhere.
  • Delegate permissions of All mailbox to Admin Account.
  • Disable Unified Messaging (UM)
Migrate
  • Add & Verify Domain in Office 365
  • Create Users in Office 365.
  • Create a Migration list.
  • Connect Office 365 with On-Premises email Services.
  • Create & Start Migration Batches.
  • Complete Migration.
  • Email Routing
  • Clear Migration batches
  • Complete post-migration tasks
Reference
https://docs.microsoft.com/en-us/exchange/mailbox-migration/perform-a-staged-migration/perform-a-staged-migration
 
Hybrid Migration
 
This migration type is suitable for the below scenario.
 
Use this type of migration to maintain both on-premises and online mailboxes for your organization and to gradually migrate users and email to Office 365. Use this type of migration if,
  • You have Exchange 2010 and more than 150-2,000 mailboxes.
  • You have Exchange 2010 and want to migrate mailboxes in small batches over time.
  • You have Exchange 2013.
Option 1 - Exchange 2010
 
Prepare
  • One or more of Exchange 2010 SP3 configured with Client Access & Hub Transport roles.
  • Active Directory synchronization server
  • Exchange 2010 SP3 configured in a hybrid deployment must have one of the following operating systems installed:
  • 64-bit edition of Windows Server 2008 Standard Service Pack 2
  • 64-bit edition of Windows Server 2008 Enterprise Service Pack 2
  • 64-bit edition of Windows Server 2008 R2 Standard Service Pack 1
  • 64-bit edition of Windows Server 2008 R2 Enterprise Service Pack 1
  • Additionally, the following prerequisites must be installed:
  • .NET Framework 3.5 SP1
  • Internet Information Services (IIS)
  • Windows PowerShell V2.0
  • Windows Remote Management V2.0
  • Active Directory Federation Services Servers (Optional)
  • Active Directory Synchronization Server
  • In the Active Directory site where your existing Exchange 2010 servers are deployed, you must have at least one writeable domain controller running any of the following:
  • Windows Server 2003 Standard Edition with SP1 or later (32-bit or 64-bit)
  • Windows Server 2003 Enterprise Edition with SP1 or later (32-bit or 64-bit)
  • Windows Server 2008 Standard or Enterprise RTM or later (32-bit or 64-bit)
  • Windows Server 2008 R2 Standard or Enterprise RTM or later
  • Windows Server 2008 Datacenter RTM or later
  • Windows Server 2008 R2 Datacenter RTM or later
 Migrate
  • Add & Verify Domain in Office 365
  • Synchronize Users to Office 365.
  • Configure Authentication model. (Cloud Only or Federated or Pass-Through)
  • Configure DNS & Exchange certificates.
  • Configure Exchange Web Services.
  • Configure Hybrid Services.
  • Create Migration list.
  • Connect Office 365 with On-Premises email Services.
  • Create & Start Migration Batches.
  • Complete Migration.
Option 2 - Exchange 2013
 
Prepare
  • Exchange 2013 servers configured with the Client Access and Mailbox server roles. All on-premises Exchange 2013 servers must have the latest Exchange 2013 cumulative update available installed in your on-premises organization
  • An Active Directory synchronization server running Azure Active Directory Connect.
  • Exchange 2013 servers configured in a hybrid deployment must have one of the following operating systems installed:
  • 64-bit edition of Windows Server 2008 R2 Datacenter RTM or later
  • 64-bit edition of Windows Server 2008 R2 Standard Service Pack 1
  • 64-bit edition of Windows Server 2008 R2 Enterprise Service Pack 1
  • 64-bit edition of Windows Server 2012 Standard or Datacenter
  • In the Active Directory site where your existing Exchange 2010 servers are deployed, you must have at least one writeable domain controller running any of the following:
  • Windows Server 2003 Standard Edition with SP1 or later (32-bit or 64-bit)
  • Windows Server 2003 Enterprise Edition with SP1 or later (32-bit or 64-bit)
  • Windows Server 2008 Standard or Enterprise RTM or later (32-bit or 64-bit)
  • Windows Server 2008 R2 Standard or Enterprise RTM or later
  • Windows Server 2008 Datacenter RTM or later
  • Windows Server 2008 R2 Datacenter RTM or later
  • Windows Server 2012 Standard or Datacenter
  • Additionally, the Active Directory forest must be Windows Server 2003 forest functional level or higher.
Migrate
  • Add & Verify Domain in Office 365
  • Synchronize Users to Office 365.
  • Configure Authentication model. (Cloud Only or Federated or Pass-Through)
  • Configure DNS & Exchange certificates.
  • Configure Exchange Web Services.
  • Configure Hybrid Services.
  • Create Migration list.
  • Connect Office 365 with On-Premises email Services.
  • Create & Start Migration Batches.
  • Complete Migration.
Option 3 - Exchange 2016
 
Prepare
  • One or more Exchange 2016 servers configured with the Mailbox server role. All on-premises Exchange 2016 servers must have the latest release, or the immediately previous release, of Exchange 2016 installed to support hybrid functionality with Office 365.
  • An Active Directory synchronization server running Azure Active Directory Connect.
  • Exchange 2016 servers configured in a hybrid deployment have the same system requirements as standard Exchange 2016 deployments.
  • In the Active Directory site where your existing Exchange 2016 servers are deployed, you must have at least one writeable domain controller running any of the following:
      • Windows Server 2012 R2 Standard or Datacenter
      • Windows Server 2012 Standard or Datacenter
      • Windows Server 2008 R2 Standard or Enterprise
      • Windows Server 2008 R2 Datacenter RTM or later
      • Windows Server 2008 Standard, Enterprise, or Datacenter
  • Additionally, the Active Directory forest must be Windows Server 2008 forest functional level or higher.
Migrate
  • Add & Verify Domain in Office 365
  • Synchronize Users to Office 365.
  • Configure Authentication model. (Cloud Only or Federated or Pass-Through)
  • Configure DNS & Exchange certificates.
  • Configure Exchange Web Services.
  • Configure Hybrid Services.
  • Create Migration list.
  • Connect Office 365 with On-Premises email Services.
  • Create & Start Migration Batches.
  • Complete Migration.
Minimal Hybrid
 
Prepare
 
Use minimal hybrid to migrate emails if you:
  • Are running at least one Exchange 2010, Exchange 2013, and/or Exchange 2016 server on-premises.
  • Plan to move to Exchange Online over a course of few weeks or less.
  • Do not plan to continue to run directory synchronization to manage your users.
Migrate
  • Add & Verify Domain in Office 365
  • Synchronize Users to Office 365.
  • Configure Minimal Hybrid Configuration.
  • Start User mailbox migration.
  • Configure DNS.

Exchange Online to Exchange Online Migration (Tenant to Tenant)

 
Office 365 does’t support or provide any tool for Tenant to Tenant migration. This can be done through 2 Methods.
  1. PST Migration
  2. 3rd Party Tool.
PST Migration
  • PST files to be stored in centralized storage.
  • Office 365 Import feature can be utilized to migrate the data. This can be performed in 2 Ways.
    1. Network Import
    2. Ship Drives.
Network Import can be used to upload the data to Azure Storage & then map it to Office 365 Mailbox.
 
Ship Drives option allows customers to copy their data to hard drive and ship the drive to the Microsoft physical location. The data import will be performed at back end.
 
PST migration is recommended for the Office 365 tenant with Exchange Online (EXO) Services alone. Incase of a tenant with SharePoint Online (SPO) or OneDrive for Business (ODB) , then it is advisable to use the 3rd party tool as it gives option to migrate all Office 365 Data (EXO, SPO & ODB) in single console. There is no inbuilt tool provided by Microsoft to migrate SPO & ODB data.
 
3rd Party Tool
 
One of the best migration tool for this scenario is Migration Wiz by Bittitan.
 
Migration Guide for the same is available here.
 

Other Email Services to Exchange Online Migration

 
IMAP Migration
 
You can use the Internet Message Access Protocol (IMAP) to migrate user emails from Gmail, Yahoo, Outlook.com, and other email systems that support IMAP protocol. When you migrate the user's email by using IMAP migration, only the items in the users' inbox or other mail folders are migrated. Contacts, calendar items, and tasks can't be migrated with IMAP, but they can be by a user.
  • You can only migrate items in a user's inbox or other mail folders. This type of migration doesn't migrate contacts, calendar items, or tasks.
  • You can migrate a maximum of 500,000 items from a user's mailbox (emails are migrated from newest to oldest).
  • The biggest email you can migrate is 35 MB.
Prepare
  • Gather end-user credentials of Source email system.
  • Enable “Less Secure App”. (This Option depends on the Service Provider)
  • Disable Multi-Factor authentication or 2-Step verification.
Migrate
  • Add & Verify Domain in Office 365
  • Connect Office 365 with Source email System.
  • Create & Start Migration Batches
  • Email Routing
  • Clear Migration batches
  • Assign licenses to Office 365 users.
Note
It is advisable to migrate all mailboxes in single batch and perform the Email routing once all the mailboxes are migrated.
 
Also, clearing migration batches should be performed after 48 Hours of Email routing changes, to avoid any data loss.
 
G suite to Office 365 Migration (inbuilt Tool)
 
Recently, Microsoft & Google have provisioned a new migration method to migrate data from G Suite to Office 365. This migration method overcomes the drawback of IMAP migration which is a manual import of Calendar & Contacts. Also, it provides an option to migrate the data in batches and allow the migrated users to start using the Office 365 services while their pal’s mailboxes are being migrated.
 
Prepare
  • Create Service Account in G Suite.
  • Enable API
  • Add Domain Alias & New Domain in G Suite.
Migrate
  • Add & Verify Domain in Office 365
  • Create Mail User objects in Office 365
  • Connect Office 365 with G Suite Services.
  • Create & Start Migration Batches.
  • Complete Migration Batches.
  • Email routing update.
Third-Party Tool & PST migration details remain the same as explained in Exchange Online to Exchange Online Migration (Tenant to Tenant).