Zoning provides access control in the SAN topology. Zoning defines which HBAs can connect to which targets. When you configure a SAN by using zoning, the devices outside a zone are not visible to the devices inside the zone.
Zoning has the following effects:
Reduces the number of targets and LUNs presented to a host.
Controls and isolates paths in a fabric.
Can prevent non-ESXi systems from accessing a particular storage system, and from possibly destroying VMFS data.
Can be used to separate different environments, for example, a test from a production environment.
With ESXi hosts, use a single-initiator zoning or a single-initiator-single-target zoning. The latter is a preferred zoning practice. Using the more restrictive zoning prevents problems and misconfigurations that can occur on the SAN.
For detailed instructions and best zoning practices, contact storage array or switch vendors.