NPIV limitations when used to virtualize Fibre Channel ports are as follows:
NPIV ports may not be used for booting.
NPIV ports are best used in SANs with a relatively small number of ports, either virtual or physical. Also, some targets might not have enough resources to process the large number of ports that NPIV can create. This limitation exists because processing state change notifications (SCN) on the SAN takes significant time if a large number of ports are on the SAN. You can work around this limitation on a large SAN by using zoning, which can limit the number of visible ports.
MPxIO can be used with NPIV, although you should ensure that different paths are physically redundant.
NPIV is supported only in a Fabric topology, and not in an FC-AL or point-to-point topology.
Not all hardware supports NPIV. Both switches and HBAs (although not targets) must support NPIV in a SAN. By specification, HBAs should support up to 255 virtual ports, although this capability is defined by the resources on the switch. Switches might have to be updated to the latest firmware levels for NPIV support.