Fibre Channel Interfaces

Each storage system with Fibre Channel interfaces has a unique 64-bit WWNN of the form 56:C9:CE:90:xx:xx:xx:00, where the xx:xx:xx is generated pseudo-randomly as part of the setup process. Each interface has a unique 64-bit WWPN where the last octet is numbered sequentially starting from 01. Unlike iSCSI interfaces, the WWPN is not shared between controllers. Rather, the WWPNs are numbered in order from the lowest interface to the highest interface (for example, fc1.1, fc2.1, fc5.1, etc.) starting first with controller A, and then controller B. If you add an additional card or cards of Fibre Channel interfaces in the future, the original cards will keep their WWPNs, and the new cards will get the next available sequence of WWPNs after the rescan is initiated with the CLI command fc update_config.

This predictable WWN scheme allows you to do things like plan a maintenance window to switch zoning before a new storage array arrives. To do this, use the fc regenerate_wwn wwnn_base command to alter the WWNN base. The WWNN base can be any value between 00:00:01 and FF:FF:FF (inclusive). When the WWNN base is changed, the WWPNs are also renumbered back to their default order as described above.

NOTE: All Fibre Channel interfaces must be both administratively and operationally offline before proceeding. After the regenerate completes, all interfaces will be brought back online.

NOTE: It is the customer’s responsibility to avoid having duplicate WWWN’s. For high availability, HPE Best Practices recommend having dual fabrics with hosts connected to both. Similar to the Even/Odd IP address zone used by iSCSI network interfaces, HPE Best Practices recommend having all odd numbered ports (01, 03, 05…) connected to one fabric and all even numbered ports (02, 04, 06…) connected to the other fabric.

See the fc command in the Command Reference for more details.