HP-UX Mass Storage Stack - Hardware Path Aliasing

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Abstract
This document describes the Hardware Path Aliasing feature contained in the HP-UX 11i v3 Mass
Storage subsystem. The hardware path name associated with mass storage objects is currently
represented as a long string of numbers, and the forward slash (/) and period (.) delimiters. This
name can be very long and difficult to remember. For example, a hardware path for a lunpath is
0/4/2/0.0x500508b300903331.0x16000000000000.
By substituting an alias for all or part of the hardware path name, you can shorten the length of the
name and associate a user-friendly name with pairs of nodes or individual nodes in the I/O tree,
where each node represents a mass storage object (HBA, target path, lunpath, or LUN). For example,
an alias for the lunpath might be fcd0.tport1.disk4175 (the HBA alias is fcd0 and the target
path alias is fcd0.tport1). Or you might want to give your target paths a more meaningful identity
like the name of the enclosure. You can also identify disks with aliases, for example boot_disk
instead of 64000/0xfa00/0x3.
After you create a hardware path alias, you can use it to replace the hardware path as the identifier
in several commands. For example, all scsimgr commands that accept an identifier of -H
hardware path also accept the hardware path alias in place of the hardware path. In addition, the
ioscan, insf, mksf, and rmsf commands accept the hardware path alias in place of the
hardware path.
ioscan command alias_path property
The ioscan command property associated with the hardware path alias is called alias_path. The
ioscan –P alias_path command displays the hardware paths along with the corresponding
hardware path aliases for the I/O system. By default, for the initial release of the hardware path
aliasing feature (HP-UX 11i v3 March 2010 release), hardware path aliases are NULL strings, and
the alias_path property for a NULL hardware path alias is displayed as N/A. The following
example shows this:
# ioscan –P alias_path
Class I H/W Path alias_path
====================================================================
fc 0 0/3/1/0 N/A
tgtpath 36 0/3/1/0.0x207000c0ffd8bee1 N/A
lunpath 1145 0/3/1/0.0x207000c0ffd8bee1.0x0 N/A
lunpath 1146 0/3/1/0.0x207000c0ffd8bee1.0x401d000000000000 N/A
ctl 4 64000/0xfa00/0x1 N/A
disk 4175 64000/0xfa00/0x36a N/A
The HP-UX 11i v3 March 2011 release implements a default hardware path aliasing scheme. The
following shows some example hardware paths along with their default hardware path aliases:
# ioscan –P alias_path
Class I H/W Path alias_path
====================================================================
fc 0 0/3/1/0 fcd0
tgtpath 36 0/3/1/0.0x207000c0ffd8bee1 fcd0.tport1
lunpath 1145 0/3/1/0.0x207000c0ffd8bee1.0x0 fcd0.tport1.ctl4
lunpath 1146 0/3/1/0.0x207000c0ffd8bee1.0x401d000000000000 fcd0.tport1.disk4175
ctl 4 64000/0xfa00/0x1 ctl4
disk 4175 64000/0xfa00/0x36a disk4175
The entries in the H/W Path column are the hardware path strings you use with the -H option to the
scsimgr, ioscan, and mksf commands without aliases. You can now use the entries in the
alias_path column in their place. If you like these default hardware path aliases, you can start to
use them after upgrading to the March 2011 release. They are assigned automatically at boot time.
For information on the default scheme, see Default hardware path aliasing scheme
.