In HP-UX 11.31, a new agile addressing scheme for mass storage devices is used.
The agile addressing scheme defines two new sets of hardware paths for each device: • The LUN hardware path: is a virtualized path, which represents the LUN independently of any of its I/O paths. • A set of lunpath hardware paths: each represents a specific I/O path to the LUN and maps to a single legacy hardware path. The format of the lunpath hardware path is different from the legacy hardware path and depends on the SCSI transport.
LUN hardware path format: The virtualized LUN hardware path is built using the following elements: • The root node of all virtual devices: by convention this has the constant address 64000. Virtual devices in the context of the I/O tree are devices for which the hardware path does not represent any physical location of the device. • The virtual bus address under which all LUN nodes are attached: by convention this has the constant address 0xfa00. • A virtual LUN identifier corresponding to the hexadecimal representation of the default minor number assigned to the device in the agile view.
So the hardware path of a LUN will always have the following format: 64000/0xfa00/0xh, where h is the hexadecimal representation of the default minor number assigned to the device
Lunpath hardware path format: The format of the lunpath hardware path is as follows: • <HBA hw path>.<target port WWN or port id>.<SCSI-3 LUNid> Where: • HBA hw path: legacy HBA hardware path (example: 0/3/1/0). • target port WWN or port id: hexadecimal representation of the target port Worldwide name (WWN), or the target port identifier if the SCSI transport does not support WWN (example: 0x21000020370fe8c8 for WWN, and 0x0 for port id). • SCSI-3 LUNid: hexadecimal representation of the SCSI-3 64 bit LUN identifier.
For more detailed information, refer the below HP Whitepaper on HP-UX 11i v3 Mass Storage Device Naming:
