HP-UX System Administrator's Guide: Overview HP-UX 11i v3 (B3921-90011, September 2010)

Lunpath Hardware Paths
This format is used for addressing LUNs in agile mode. It is identical to the legacy hardware
path format up to the host bus adapter (HBA). Beneath the HBA, two additional address elements
are represented (in hexadecimal):
Target address A transport dependent address identifying the physical device associated
with the hardware path
LUN address A 64-bit representation of the LUN identifier reported by the target.
0/2/1/0.0x50001fe1500170ac.0x4017000000000000 is an example of a SCSI-3 hardware
path.
Figure 3-4 Lunpath Hardware Path Components
HBA Path
0/2/1/0.0x50001fe1500170ac.0x4017000000000000
Target Address LUN Address
LUN Hardware Paths
Because devices can have multiple physical hardware paths, a virtualized LUN hardware path is
needed so that the hardware path that a persistent device special file maps to remains the same
even when the underlying physical hardware path elements change.
Instead of a series of bus-nexus addresses (corresponding to specific hardware paths) leading to
the HBA, virtual hardware paths use a virtual bus-nexus (known as the virtual root node) with
an address of 64000. Addressing beneath that virtual root node consists of a virtual bus address
and a virtual LUN ID, delimited by slash characters (“/”).
64000/0xfa00/0x22 is an example of a virtual hardware address.
Figure 3-5 LUN Hardware Path Components
64000/0xfa00/0x22
Virtual
Root
Node
Virtual
Bus
Address
Virtual
LUN ID
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