A customer has data in a LUN on an existing third-party SAN storage system that...

To migrate data from a LUN on an existing third-party SAN storage system to a new NetApp AFF A400 all-flash MetroCluster system, the supported methods include:

Foreign LUN Import in online mode: This method allows for data migration without significant downtime, enabling the system to continue serving data while the migration process is ongoing.

Foreign LUN Import in offline mode: This method involves taking the LUN offline during the migration process, which may be necessary in certain scenarios to ensure data integrity.

For more details, refer to:

NetApp Documentation on Foreign LUN Import

NetApp Community on LUN Import Methods