N_Port ID Virtualization (NPIV)
As a Storage and Server administration I spend most of my time on HP Blade servers. I must admit, Blade
server and chassis technology is awesome. Cabling is always a hassle if server needs to connect to FC and
IP network. Blade Servers will save a lot of time when it comes to administration, space in datacenter(DC)
and get rid of lot of cabling. Zoning is a regular thing we do, I always have this confusion how exactly this
NPIV is working in case of HP Blade server. So I believe there are folks like me who also have this issue in
understanding this technology. So, I am trying here to give some guidance on it.
Why we need NPIV?
First, though, I need to cover some basics. This is unnecessary for those of you that are Fibre Channel
experts, but for the rest of the world it might be useful:
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N_Port: An N_Port is an end node port on the Fibre Channel fabric. This could be an HBA (Host
Bus Adapter) in a server or a target port on a storage array.
F_Port: An F_Port is a port on a Fibre Channel switch that is connected to an N_Port. So, the port
into which a server’s HBA or a storage array’s target port is connected is an F_Port.
E_Port: An E_Port is a port on a Fibre Channel switch that is connected to another Fibre Channel
switch. The connection between two E_Ports forms an Inter-Switch Link (ISL).
Normally, an N_Port would have a single N_Port_ID associated with it; this N_Port_ID is a 24-bit address
assigned by the Fibre Channel switch during the FLOGI process. The N_Port_ID is not the same as the
World Wide Port Name (WWPN), although there is typically a one-to-one relationship between WWPN and
N_Port_ID. Thus, for any given physical N_Port, there would be exactly one WWPN and one N_Port_ID
associated with it.
What NPIV does is allow a single physical N_Port to have multiple WWPNs, and therefore multiple
N_Port_IDs, associated with it. After the normal FLOGI process, an NPIV-enabled physical N_Port can
subsequently issue additional commands to register more WWPNs and receive more N_Port_IDs (one for
each WWPN). The Fibre Channel switch must also support NPIV, as the F_Port on the other end of the link
would “see” multiple WWPNs and multiple N_Port_IDs coming from the host and must know how to handle
this behavior.
Once all the applicable WWPNs have been registered, each of these WWPNs can be used for SAN zoning or
LUN presentation. There is no distinction between the physical WWPN and the virtual WWPNs; they all
behave in exactly the same fashion and you can use them in exactly the same ways.
So why might this functionality be useful? Consider a virtualized environment, where you would like to be
able to present a LUN via Fibre Channel to a specific virtual machine only:
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Without NPIV, it’s not possible because the N_Port on the physical host would have only a single
WWPN (and N_Port_ID). Any LUNs would have to be zoned and presented to this single WWPN.
Because all VMs would be sharing the same WWPN on the one single physical N_Port, any LUNs
zoned to this WWPN would be visible to all VMs on that host because all VMs are using the same
physical N_Port, same WWPN, and same N_Port_ID.
With NPIV, the physical N_Port can register additional WWPNs (and N_Port_IDs). Each VM can
have its own WWPN. When you build SAN zones and present LUNs using the VM-specific WWPN,
then the LUNs will only be visible to that VM and not to any other VMs.
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The below figure belong to the HP c7000 chassis box. If you have noticed there are 16 blade
servers whose HBA cards are been connected to VC-FC module. A VC-FC module have a 4 8Gbps
FC ports. Every 4 servers are connected to HBA-Integrator. It’s a HBA card on the VC-FC module
which 8Gb speed. The NPIV was been enabled on the HBA-Integrator and FC switch. For the zoning
purposes each HBA on the blade server should have a WWNN and WWPN. The HBA Aggregator will
create a virtual WWNN and WWPN and assign to each server. This will show in the name server of
the FC switch. These are used for the zoning services.
For example, server having a EMULEX HBA , WWN starts with 10:00:x:x:x:x:x:x:x. If this HBA is
on a Blade server connected to a VC-FC module, you can see the WWNN and WWPN for the server
starts with 50:x:x:x:x:x:x:x:x:x. From the host side , EMULEX OneCommand Manager(Earlier
HBAnywhere) will show the as below in Picture 3.
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The above picture shows the EMULEX OneCommand manager. The WWN red border is the original WWN number of the
EMULEX HBA card. It starting with 10:x. The next WWN in the black border is the NPIV WWNP of the Emulex HBA. This is
generated by the Virtual Connect. The last WWN in green box is the WWN unique identifier of the EMC Clariion. In the
Fabric switch, only the NPIV port visible for the zoning. The following figure shows the HP c7000 front & Rear view and
setting in the HP FC-VC where the NPIV WWNs are generated. The below chassis contains 8-Half eight servers and 4 fullheight servers.
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The green borderd device is the HP FC-Virtual Connect which contains 4 X 8Gb ports connecting to the FABRIC SWITCH.
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Why I need to use NPIV:
1. We connected 16 server, but the cables we used is only “4”. These 4 cables are from the FC-VC to the Fabric Switch.
Less complex job.
2. If we need to connect these servers to the fabric, we need to have 16-ports on the FC switch. But using NPIV , we
used only 4 ports.
3. If we need to assign any LUNs to a Virtual Machine environment directly, we need to use this NPIV. For more
information on this, search for NPIV in VMware.
4. Even we can connect 16 servers, the space used s 10U in a rack. A minimum server will be a 1U(DL 360), which
configure 16U size in your rack along with cabling.
Document References:
HP Virtual Connect technology for the HP BladeSystem C-Class:
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00814156/c00814156.pdf
Understanding NPIV and NPV:
http://blog.scottlowe.org/2009/11/27/understanding-npiv-and-npv/
HP Virtual Connect for C-Class BladeSystem User Guide:
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00865618/c00865618.pdf
The HP Virtual Connect for Dummies:
http://up2v.files.wordpress.com/2010/04/hp-virtual-connect-for-dummies.pdf
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