LUN hardware path and lunpath hardware path

[Abubakkar]

Dear Friends,

Please explain what is mean LUN hardware path 64000/0xfa00/0x0 and  lunpath hardware path  0/1/1/1.0x3.0x0

[pradeep m · Accepted solution]

Hi,

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:

http://bizsupport.austin.hp.com/bc/docs/support/SupportManual/c01906504/c01906504.pdf