LEARN. PRACTICE. GROW.Concept and mechanism
FC zoning limits which ports can communicate in the fabric. LUN mapping controls presentation of the resource to authorized initiators. These are complementary checks: communicating with a target does not mean access to all its LUNs. In the ONTAP examples, igroups collect FC initiator WWPNs or iSCSI node names. The documented zoning design uses one initiator port with the required target LIFs. For ONTAP targets, confirm logical LIF WWPNs instead of automatically using physical node-port WWPNs. Keep these rules tied to the referenced implementation without generalizing naming conventions to every vendor.
Guided application
Replacing an HBA can change its WWPN and leave old references in zoning and the igroup. An active physical link does not resolve that mismatch. Reconcile the new identity with the change request and validate approved access. For resilience, draw complete paths: two cables on the same switch do not tolerate losing that switch. Before maintaining one fabric, confirm the alternative is functioning and supported. In a fictional scenario, path B is already faulty when the window to restart A arrives. Restoring B or revising the window avoids removing the only functioning route under approval that did not allow a complete outage.
The design has two fabrics; the window must consider how many function now.
Common pitfalls
Zoning as mapping; link as authorization; two cables as two failure domains; nominal design as current state.
Related topics: Topology and identity · iSCSI: sessions and security · Multipathing and path states
Validate access and redundancy on the actual path before intervention.
Reference: ONTAP FC and FCoE zoning concepts · DR SAN 2026-09; selected RHEL 9, ONTAP 9 and iSCSI behavior