Types of Microsoft 365 migration (previously called Office 365 migration) include the following:
As with most migrations, a Microsoft 365 migration can work in either of two ways: over time in a phased migration, or all at once in a cutover migration.
Phased migration (also known as staged migration or batched migration)
A phased migration involves splitting your project into manageable batches of users and workloads, which are migrated in turn over a period of days, weeks, months or even years. A phased migration is usually a wise choice for any but the smallest of Office 365 migration projects. It spreads out the workload impact on the project team and support staff, and it enables you to tailor processes and communications for each group as the project proceeds. In some cases, it is the only migration method available; for instance, staged migration is the only Microsoft-supported method for migrating from legacy versions of Exchange Server (2003–2007) to Exchange Online.
A vital element for success in a phased migration is coexistence: Users must be able to continue to work and collaborate as usual throughout the project, regardless of which data and workloads have been migrated to date. For example, you need to make sure everyone can continue to access their email and schedule meetings with other users, regardless of anyone’s migration status.
Cutover (big bang) migration
In a cutover migration, everything in the scope of the project is moved in short period of time, often a single weekend. This is most straightforward migration process since it eliminates the need to plan for coexistence. And it can be an attractive option in organizations in which users wear so many hats and serve on so many project teams that it is difficult to define clear batches of users for a phased migration.
However, cutover migration is feasible only for very small projects. For instance, even though the official limit for Exchange Online migrations is 2,000 users, Microsoft recommends migrating no more than 150 mailboxes at once because of the time required to create the target users and migrate the data. In addition, the APIs for migrating cloud workloads like SharePoint Online and Teams have limitations in place to protect service availability, so the cutover migration method may not be viable for larger and more complex tenants.
In addition, cutover migrations put the organization at more risk compared to a phased migration; proceeding in small batches makes it far easier to roll back changes if something goes wrong and thereby avoid prolonged business disruption.
A Microsoft 365 migration empowers organizations to transform how they operate and collaborate. Key benefits include:
A successful Office 365 migration plan includes the following steps:
Many organizations do not migrate all their data and workloads to Microsoft 365. Instead, they adopt a hybrid IT ecosystem that includes both on-premises and cloud environments. Common drivers for choosing a hybrid infrastructure include business-critical legacy applications that have no easy migration path and strict compliance mandates that require close control over regulated data.
The steps in the migration process are largely the same as for any Microsoft 365 migration. However, you also need to integrate your on-premises Active Directory with Entra ID to provide a unified user experience across both environments. A common strategy is to use Microsoft Entra Connect (formerly Azure AD Connect) to synchronize user accounts and credentials between those directories.
The cost of Microsoft 365 migration projects can vary dramatically depending on project scope and complexity. Key costs include the following:
Choosing the best tool for your migration involves evaluating multiple factors. Cost, as discussed above, is clearly one criterion. Others include:
Quest offers a Migration Matcher that makes it easy to find the right migration tool to meet your needs and goals.