A state university puts a host WWPN in a zone with an array, but the Fibre Channel name server on the MDS has no entry for that host. The host has not completed FLOGI. Why is the name server empty for it?
Select an answer to reveal the explanation.
Short Explanation
The name server is a sign-in sheet, and zoning is the invitation list. You see a WWPN in the name server only after FLOGI, so a zoned host that has not logged in stays absent. Activating the zoneset does not sign the host in.
Full Explanation
The Fibre Channel name server is the fabric directory of devices that have logged in. A successful FLOGI creates the entry, including the WWPN and the assigned FCID. Zoning is a separate database that says which logged-in devices may communicate. The university can zone a WWPN that is powered off, and the name server stays empty for that host until it completes FLOGI. The zone database is not the name server. A WWPN in a zone is not automatically a directory entry. Activating the zoneset updates the active zoning configuration. It does not synthesize name-server records for members that are offline. The principal switch priority is used to elect the switch that coordinates domain IDs. It is not a name-server record, and winning the election does not insert host WWPNs. Caveat: a host can be in the name server and still be unable to reach the array if it is missing from the active zone, so an FCNS entry is not proof that zoning is correct. Operational check: have the host log in, confirm the WWPN appears in the name server with an FCID, and only then compare that entry with the active zone.