Database Migration Service supports the following backup types for homogeneous SQL Server migrations to Cloud SQL.
- Full backups
- Full backups are the backbone of the migration process. They contain all the data in your database at the point in time when you export them. The full backup file is required for migration.
- Differential backups
- Differential backups contain all the source data that appeared in your database since the last full backup file. Differential backups are useful if you have a lot of data to replicate and want to handle it in bulk rather than upload multiple transaction log files. The differential backup file is optional for migration.
- Transaction log files
- These files contain a list of change operations
that take place in your database. Database Migration Service uses this information
to replicate data updates in your destination database during the
Change Data Capture (CDC) phase.
For homogeneous SQL Server migrations, Database Migration Service supports only the continuous migration type (for more information see Continuous migrations data flow). This means that migration jobs always proceed to the CDC phase, but you don't get errors if you don't upload any transaction log files. If you don't upload any transaction log files, you need to promote the migration job when the initial load phase is over. See Promote a migration job.
As you prepare the backup files for your migration, make sure you consider the following:
Naming conventions: Each backup file type needs to use a specific naming convention. See Prepare your backup files.
Folder structure: Each backup file type needs to be stored in a separate folder in the Cloud Storage bucket you use for migration. See Store backup files in a Cloud Storage bucket.
Encryption: You can use encrypted backups for your migration. If you want to encrypt the backup files, you need to encrypt all types of backup files you use for a specific database included in your migration. See Use encrypted backup files.
Migration job configuration: If you use a differential backup file for any database included in your migration, you need to configure the migration job so that Database Migration Service can recognize the differential backup files in your Cloud Storage bucket. See Create a migration job
What's next
For a detailed step-by-step migration guide, see Cloud SQL for SQL Server migration guide.