Fibre Channel and FCoE zoning overview

Contributors

An FC, FC-NVMe or FCoE zone is a logical grouping of one or more ports within a fabric. For devices to be able see each other, connect, create sessions with one another, and communicate, both ports need to have a common zone membership. Single initiator zoning is recommended.

Reasons for zoning

  • Zoning reduces or eliminates crosstalk between initiator HBAs.

    This occurs even in small environments and is one of the best arguments for implementing zoning. The logical fabric subsets created by zoning eliminate crosstalk problems.

  • Zoning reduces the number of available paths to a particular FC, FC-NVMe, or FCoE port and reduces the number of paths between a host and a particular LUN that is visible.

    For example, some host OS multipathing solutions have a limit on the number of paths they can manage. Zoning can reduce the number of paths that an OS multipathing driver sees. If a host does not have a multipathing solution installed, you need to verify that only one path to a LUN is visible by using either zoning in the fabric or a combination of Selective LUN Mapping (SLM) and portsets in the SVM.

  • Zoning increases security by limiting access and connectivity to end-points that share a common zone.

    Ports that have no zones in common cannot communicate with one another.

  • Zoning improves SAN reliability by isolating problems that occur and helps to reduce problem resolution time by limiting the problem space.

Recommendations for zoning

  • You should implement zoning any time, if four or more hosts are connected to a SAN or if SLM is not implemented on the nodes to a SAN.

  • Although World Wide Node Name zoning is possible with some switch vendors, World Wide Port Name zoning is required to properly define a specific port and to use NPIV effectively.

  • You should limit the zone size while still maintaining manageability.

    Multiple zones can overlap to limit size. Ideally, a zone is defined for each host or host cluster.

  • You should use single-initiator zoning to eliminate crosstalk between initiator HBAs.