Overview: The Next Generation Mass Storage Stack (September 2009)

disk using its agile form. If the system was updated rather than installed, lvlnboot displays the root disk in its
legacy form.
A new LVM utility, vgdsf, converts existing volume group configuration information from legacy to persistent
DSFs.
You can manage alternate links to a multi-pathed device outside of LVM using the next generation mass storage
stack. By default, the mass storage stack balances the I/O load across all available paths to a disk. However, you
can use the scsimgr command to emulate LVM PVLink functionality and to handle LUN failure and load
balancing. For more information, see Disabling Multi-Pathing on Legacy DSFs
.
Note: LVM continues to support alternate links to a device, but their use is no longer required or recommended.
LVM also supports dynamic LUN expansion. If you increase the size of a LUN, use the vgmodify command to
incorporate the additional space into the volume group. LVM does not support dynamic LUN contraction or block
size changes. If either of these events occurs, LVM marks the LUN as unavailable.
Even though the I/O subsystem supports disks larger than 2 TB, LVM only accesses the first 2 TB of any disk.
For more information about LVM in HP-UX 11i v3, see the white papers in the For more
information section.
Offline Diagnostic Environment
The Offline Diagnostic Environment (ODE) has a switch to display either the legacy or agile view. On PA-RISC
servers, ODE displays lunpath hardware paths in BCH format (described in PA-RISC Boot Subsystem
) in both
decimal and hexadecimal. On Integrity servers, ODE displays lunpath hardware paths in hexadecimal only.
PA-RISC Boot Subsystem
On PA-RISC systems, the boot console handler (BCH) locates boot devices and launches preboot applications. The
boot loader (hpux) loads and launches the operating system. Both the BCH and boot loader are limited to 32-bit
address elements, which impacts the mass storage stack as follows:
• If the boot path was set using the agile view, the BCH PATH command displays the lunpath hardware
path in a different format from the setboot or ioscan –N command. If the boot path includes any 64-
bit elements, the BCH displays them as two 32-bit numbers. For example, if the primary boot path is
0/2/1/0.0x500508b300903331.0x4002000000000000, the BCH displays the following:
Primary boot path: 0/2/1/0.1342507187.9450289.1073872896
0/02/01/0.500508b3.903331.40020000(hex)
The leading 0x is omitted, the path elements are split into 32-bit parts, and the last 8 zeroes are omitted.
Older systems may print the primary boot path in decimal only. You must manually convert the address to
recognize the hexadecimal path elements.
• When using the BCH to enter a lunpath hardware path in the BOOT or PATH commands, you must use the
32-bit format. For example:
Main Menu: Enter command > PA PRI 0/2/1/0.0x500508b3.0x903331.0x40020000.0x0
• The BCH SEArch command prints legacy hardware paths only. To display lunpath hardware paths in
BCH format, use the ioscan command with the –e option.
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