We are having a devil of a time trying to migrate our current on-premises SQL Server to an Azure SQL Database. It is large but not that large (about 300 GB). We've tried the "Publish to Azure" option from SQL Server and get errors and exceptions (out of memory exceptions). The Data Migration Assistant seems to start working OK, but it fails after 12 hours or so having completed only about 15% of the migration. We can't be down for 12 hours, let alone the time it would seem to take in order to move the complete 300 GB database.
What are some strategies and best practices that we could try for the data migration that would minimize downtime?