Beginning in ONTAP 9.3, you can modify the default process by which domain controllers (DCs) are discovered. This enables you to limit discovery to your site or to a pool of preferred DCs, which can lead to performance improvements depending on the environment.
By default, the dynamic discovery process discovers all available DCs, including any preferred DCs, all DCs in the local site, and all remote DCs. This configuration can lead to latency in authentication and accessing shares in certain environments. If you have already determined the pool of DCs that you want to use, or if the remote DCs are inadequate or inaccessible, you can change the discovery method.
In ONTAP 9.3 and later releases, the discovery-mode parameter of the cifs domain discovered-servers command enables you to select one of the following discovery options:
The default-site parameter for the SMB server must be defined to use this mode.
To use this mode, you must first define the preferred DCs for the SMB server.
Discover all available DCs (default).
Limit DC discovery to your site.
Use only preferred DCs and not perform discovery.