SQL Server AlwaysOn Automatic initialization of AG (ii)

Required conditions

• File path requirements

In SQL Server 2016, automatic seeding requires that the data and log file paths be the same on every instance of SQL Server participating in the availability group. In SQL Server 2017, you can use a different path, but Microsoft recommends that you use the same path when all replicas are hosted on the same platform (for example, Windows or Linux). Cross-platform availability groups have different paths for replicas. If your data file is on a different volume on a replica, the behavior of SQL Server 2017 can meet your needs. See the Disk Layout section of Microsoft's official documentation for details.

• Port Access Requirements

The availability group seeding communicates through the database mirroring endpoint. Turn on the inbound firewall rules for each server mirroring the endpoint ports.

• Recovery model and backup requirements

The databases in the availability group must be in the full recovery model. The database needs to have the most recent full and transaction log backups. These backup files are not used for automatic seeding, but these files are required to include the database in the availability group.

SQL Server AlwaysOn Automatic initialization of AG (ii)