You can use Azure Database Migration Service to perform offline and online migrations. With an offline migration, application downtime starts when the migration starts. With an online migration, downtime is limited to the time to cut over at the end of migration. We suggest that you test an offline migration to determine whether the downtime is acceptable; if not, do an online migration.
Note
Using Azure Database Migration Service to perform an online migration requires creating an instance based on the Premium pricing tier. For more information, see the Azure Database Migration Service pricing page.