HP-UX System Administrator's Guide: Routine Management Tasks

Storage Area Management
(http://docs.hp.com/en/netsys.html#Storage%20Area%20Management).
HP-UX 11i v3 Device Special Files
HP-UX 11i v3 introduces persistent DSFs (Device Special files) for mass storage devices.
A single persistent DSF is created for each LUN, not bound to the path to the device
as in prior HP-UX releases, but to the LUN’s Worldwide Identifier (WWID), a unique
and permanent identifier of the LUN. This makes the DSF persistent and agile, that is,
independent from the physical paths to the device. This also enables transparent
multi-pathing, meaning that any available path to the device can transparently be
selected to access it. An example of persistent DSF name is /dev/disk/disk13.
NOTE: Persistent DSFs will remain persistent for the life of a system, even after a
recovery. However, they are not persistent if you cold reinstall an HP-UX 11i v3 system.
HP-UX 11i v3 Hardware Paths
HP-UX 11i v3 introduces a new representation of hardware paths for mass storage
devices, referred to as a lunpath hardware path, which coexists with the legacy
representation of hardware paths already used in versions prior to HP-UX 11i v3.
The lunpath hardware path format enables the use of more targets and LUNs than are
permitted in the legacy addressing scheme. It is identical in format to a legacy hardware
path, up to the HBA, and represents the same path to the LUN. Beyond the HBA,
additional elements representing a transport-dependent target address (for instance,
a target port World-Wide Name for Fibre Channel or a port id for SCSI) and a 64-bit
SCSI LUN address, are printed in hexadecimal.
Note: the hardware path elements size has been increased from 8 bits to 64 bits to fit
these additional elements.
The lunpath hardware path format may be used to specify boot paths as explained
further in this section.
Booting HP-UX on HP Integrity Servers: Details and Variations
HP-UX System Administrator’s Guide: Overview describes the basic sequence of events
that occurs when you turn on, reset, or reboot an HP Integrity Server. This section
covers the boot process more thoroughly because there are times when you will need
to manually control the boot process; for example:
• When you need to boot your system from a device other than the device from
which you normally boot.
• When you need to boot your system from a kernel file other than the kernel file
from which you normally boot.
• When you need to boot the system into Single-User Mode to ensure that special
tasks you are doing are not affected by other users of the system.
38 Booting and Shutdown