The source and target environments must be properly prepared before starting any migration activities. Environment Preparation Checklist of this document contains a checklist of the tasks to prepare the environments.
Basic Migration Steps
Since most lab environments are not true mirror images of production, there may be some differences in behavior when you start migration in production. Therefore, the best practice is to begin your migration with a pilot migration: select a pilot group of accounts that includes a wide spectrum of groups, users, and service accounts, and migrate that group first. This limits the user impact if unexpected issues occur. Do not limit the pilot to just IT or the migration project team members because they generally have modified configurations and won’t represent a good cross-section of your users.
During the pilot migration, follow the procedures in the cookbook you prepared during the planning stage. If no problems occur, you can start migrating the rest of the environment. However, if a problem should arise, you should resolve it first, perform additional testing, update the cookbook to include the correct procedures, and then repeat the pilot.
Overview of Migration Scenarios
Migration Manager allows you to migrate multiple Active Directory domains and Exchange organizations at a time. Three basic migration scenarios are supported by Migration Manager:
- Active Directory Migration: You can use Migration Manager for Active Directory to migrate users and groups to another domain in the same or a different Active Directory forest. Depending on where the target domain resides, the migration scenario can be either inter-forest or intra-forest:
- The inter-forest migration scenario assumes you need to migrate users and groups to another domain in a different Active Directory forest. Either Exchange Server is not installed in the source forest or for some reason you do not want to migrate Exchange data to the target.
- The intra-forest migration scenario is used to migrate users and groups to another domain in the same Active Directory forest. If the source users already have Exchange mailboxes, you can simply reconnect these mailboxes to the new user accounts during migration.
- Exchange Migration: You can use Migration Manager for Exchange to migrate messaging and public folder data only while leaving the security accounts in the original Active Directory forests. In this case, users from one or several forests will have mailboxes in a separate Exchange organization. This deployment type is sometimes referred to as Exchange Resource Forest. This scenario is also applicable if Active Directory objects (such as user accounts, groups, and contacts) have already been migrated to the target domain by means of other migration tools, such as Active Directory Migration Tool (ADMT). In this case users log on to the target domain and you only need to migrate their Exchange data (such as mailboxes and public folders) to the target Exchange organization and decommission the source Exchange environment.
- Active Directory and Exchange Migration: In this scenario, you migrate both user accounts and mail data to the new Active Directory forest and Exchange organization. You need both Migration Manager for Active Directory and Migration Manager for Exchange for this scenario.