HP-UX vPars 6.0 N-Port ID Virtualization (NPIV) - A brief overview

Benefits of NPIV

This chapter lists a few of the benefits of attaching storage via NPIV:

Storage isolation

With shared (AVIO) storage, it is required that the VSP has access to all of the storage that is presented to the vPars.

With NPIV, the targets and LUNs are discovered by the vPar directly as soon as a vHBA is created. These LUNs need

not be accessible or even visible to the VSP.

In a nonvirtual environment, when a LUN is presented to a system, access to the LUN can be controlled by LUN masking

at the array or zoning on the SAN—both are based on the unique WWN associated with the physical HBA on the

system. The same can be achieved with NPIV HBAs when the storage or SAN administrator uses LUN masking or

zoning to restrict access—both of these can be done based on the virtual WWN (vWWN) associated with the vHBA.

This allows for storage isolation between the vPars and the VSP, even when they are sharing the same physical HBA.

Storage isolation also provides:

• Security

The NPIV LUNs assigned to the vPar are visible only to it. There is no risk of an application on the VSP or another

vPar accessing or overwriting the contents on these devices.

• Ease of storage provisioning

NPIV storage presentation doesn’t have to be a two-step process (first presenting the LUNs to the VSP and then

assigning each one to the vPars). This differentiates it from legacy AVIO storage.

With vHBAs, storage provisioning for a vPar is the same as for a standalone system.

• Traceability of storage to virtual environments

With AVIO devices, the vPars use storage that is either internal to the VSP or that are connected to the VSP over the

SAN. Since all the I/O from the vPars and the VSP share the same physical HBA, the existing tools for SAN

diagnostics and usage monitoring do not have vPar or application level traceability to the storage.

This is not the case with NPIV. Here there is a dedicated virtual connection between the virtual partition and the

SAN storage they use.

Support for applications that need unvirtualized access to storage devices

There are many applications—such as clustering, Symantec Storage Foundation (enclosure-based naming and DMP),

and SAN, and storage management applications that cannot operate with a virtualized view of storage. With NPIV,

the vPar operating system and applications have unvirtualized access to the LUNs discovered behind the vHBA, thus

enabling a host of applications.

There are some management applications like HP Replication Solutions Manager and HP Storage Essentials that have

a dependency on SNIA API support in addition to unvirtualized access to the storage. SNIA support for NPIV LUNs is

provided.

Quality of service

With NPIV, applications running in the virtual partitions can have service-level agreements assigned to them, and the

VSP and the vPar drivers ensure that these are honored by propagating them down the stack.

HP QoS is available with the HP XP24000 Disk Array. For more information about the array, please see

http://www.hp.com/go/xp24000.

SAN and storage chargeback

Since NPIV allows each vPar to have its own dedicated access to the set of storage assigned to it, SAN and storage

chargeback software can track the resources used by the vPar using the WWN associated with the vHBAs.

Multipath capability in the vPar

With NPIV, the administrator can now add multiple virtual HBA resources and configure each of them to see the same

set of LUNs. This allows for multipathing in the vPar, analogous to what can be achieved on standalone systems.