After a successful data migration, you can run a delta migration to identify and migrate any data that was updated or added after the migration completed.
What is a delta migration?
During a delta migration, the new data migration service migrates new data to your Google Workspace account. Depending on your migration source, a delta migration can include:
- Email data
- Email messages (updates any changes, such as a change to a label)
- Calendar data
- Contact data
A delta migration skips over objects that have already been successfully migrated and haven't been updated on the source account. These items are marked as skipped.
Start a delta migration in your target account
You must be signed in as a super administrator for this task.
Before you begin: If you're running a delta migration for Exchange Online data, review About Exchange Online delta migrations first.
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Sign in with a super administrator account to the Google Admin console.
If you aren’t using a super administrator account, you can’t complete these steps.
- Click Run delta migration.
When the migration is complete, you get an email with migration statistics. Any reports are attached.
About Exchange Online delta migrations
- If you map a new Exchange Online user to an existing Workplace user, a delta migration copies all folders and messages from their Exchange Online account to their Workspace account.
- If you map an existing Exchange Online user to a new Workspace user, a delta migration copies only messages that were created or modified since the last migration.
- A delta migration doesn't remove any data that you copied to Workspace. If you remove a previously migrated user from your list of mapped users and then run a delta migration, the user's copied data remains in Workspace.
- If a previously migrated message is moved from FolderA to FolderB in Exchange Online before a delta migration, the message is moved from the Gmail label FolderA to the label FolderB during the delta migration.
- If a previously migrated folder is renamed from FolderA to FolderB before a delta migration, the corresponding label in Gmail is renamed FolderB.
- If a previously migrated calendar is renamed from CalendarA to CalendarB before a delta migration, the corresponding calendar in Google Calendar is renamed CalendarB.
- If a previously migrated event is moved from CalendarA to CalendarB before a delta migration, a new event is created in CalendarB in Google Calendar. The previous event in CalendarA isn't deleted.
- Any change to an Exchange Online event is reflected in Google Calendar after a delta migration.
- A delta migration updates contacts and labels, but doesn’t duplicate them. However, if you exit a migration and then run a new migration, contacts are duplicated.