Hi @Tuan L ,
SQL Managed Instance supports the following database migration options (currently these are the only supported migration methods):
*Azure Database Migration Service - migration with near-zero downtime.
*Native RESTORE DATABASE FROM URL - uses native backups from SQL Server and requires some downtime.
Please check the following documents for more details .
SQL Server instance migration to Azure SQL Managed Instance(overview)
Migrate your databases(quickstart guide)
Quickstart: Restore a database to Azure SQL Managed Instance with SSMS
To avoid failures and check compatibility, you can use Data Migration Assistant (DMA) to analyze your databases on SQL Server and find any issue that could block migration to a SQL Managed Instance,such as existence of FileStream or multiple log files.
In addition for large migrations (in terms of number and size of databases), we recommend that you use the Azure Database Migration Service, which can migrate databases at scale.