What Is And How NPIV Works In SAN Switch

What is NPIV In SAN Switch

NPIV is SAN switch port level virtualization feature. NPIV stands for N-Port ID Virtualization. NPIV allows multiple initiator to logged in to same single physical target port. NPIV is mostly used SAN network where ESX Host, Blade Server and UCS deployment are present.

How NPIV Works In SAN Switch

In order to understand how NPIV works in SAN switch first lets understand how a SAN connectivity works without NPIV. In usual case one initiator or host is connected to single port of SAN switch.
During FLOGI process the switch assign a FCID to initiator and the initiator is logged in to switch port.

Below is one diagram which has simple connectivity of two server to SAN switch. where two server use two ports of SAN switch to logged in.

Now in case of NPIV multiple initiator tries to login to same single physical port of SAN switch. If SAN switch port is NPIV enabled then switch port accepts request from each initiator and assign a FCID to each initiator. Once all initiator receives a FCID all of them are logged to to same physical port.

Below diagram explains the connectivity and uses of NPIV in SAN switch network. Here compute system which is similar to blade server of ESX host which has single physical HBA which connects to single SAN switch port. In back-end the compute system has multiple nodes which shares same common physical HBA. Each node of compute system has a virtual HBA having virtual WWPN.

During FLOGI Process each virtual WWPN send request to same SAN switch port and if the SAN switch port is NPIV enabled it accepts all request and assign FCID to each node or initiator. This way multiple initiator logged in same SAN switch port.

Where We Use NPIV In SAN switch

There are various uses of NPIV in SAN network but below are most common use of NPIV.
If your environment has ESX, UCS, or Blade Server Deployment then definitely your SAN switch ports are NPIV enabled.

Second common use of NPIV is that it allows masking of LUN to individuals VMs. It means if you have multiple VMs in ESX host then you can do zoning between the VMs WWPN and Storage array. Then you can share individual LUNs to particular VM.

Third common use is that it reduce messy cable connectivity of SAN network. If you have large number of server then lot of cable connection is require between server and switch which makes difficult for Data Center admin to perform physical maintenance activity. As NPIV reduce the number of connection between server and switch physical management of Data center make simpler.
Below is one of the videos which explains the purpose of NPIV and how it works. Subscribe to YouTube Channel for such videos.