HP-UX 11i v3 Installation and Update Guide, February 2007 (Initial Release)

Choosing an Installation Method
New Mass Storage Stack for HP-UX 11i v3
Chapter 346
New Mass Storage Stack for HP-UX 11i v3
HP-UX 11i v3 introduces a new representation of mass storage devices,
known as the agile view. In the agile view, disk devices and tape drives
are identified by the actual object, not by a hardware path to the object.
In addition, paths to the device can change dynamically and multiple
paths to a single device can be transparently treated as a single
virtualized path, with I/O being distributed across those multiple paths.
This representation increases the reliability, adaptability, performance,
and scalability of the mass storage stack, without the need for operator
intervention.
HP-UX 11i v3 Hardware Paths
In HP-UX 11i v3, there are three different types of paths to a device:
legacy hardware path, lunpath hardware path, and LUN hardware path.
All three are numeric strings of hardware components, with each
number typically representing the location of a hardware component on
the path to the device. These paths are described below.
•Legacy hardware path
The legacy hardware path is the format used in releases prior to
HP-UX 11i v3, and is displayed in the legacy view. It is composed of a
series of bus-nexus addresses separated by ‘/’ leading to the host bus
adapter (HBA); beyond the HBA, additional address elements are
separated by ‘.’.
• Lunpath hardware path
The lunpath format enables the use of more targets and LUNs than
are permitted under legacy hardware paths, and is printed in the
agile view. 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 are printed in hexadecimal.
• LUN hardware path
The LUN format is a virtualized path that represents all the
lunpaths to a single LUN. It is printed in the agile view. Instead of a
series of bus-nexus addresses leading to the HBA, the path contains
a virtual bus-nexus (referred as the virtual root node) with an
address of 64000. An example of a LUN hardware path is
“64000/0xfa00/0x22”.