HP-UX System Administrator's Guide: Logical Volume Management HP-UX 11i v3 (B3921-90053 September 2011) Transform used: ESS version 2.2

Version 1.0 Device Number Format
Table 2 lists the format of the device file number for Version 1.0 volume groups.
Table 2 Version 1.0 Device Number Format
Logical Volume
Number
ReservedVolume Group
Number
Major Number
0–0xff00–0xff64
0=group file
For Version 1.0 volume groups, the major number for LVM device files is 64. The volume group
number is encoded into the top eight bits of the minor number, and the logical volume number is
encoded into the low eight bits. Logical volume number 0 is reserved for the group file.
Version 2.x Device Number Format
Table 3 lists the format of the device file number for Version 2.x volume groups.
Table 3 Version 2.x Device Number Format
Logical Volume NumberVolume Group NumberMajor Number
0–0x7ff0–0x7ff128
0=group file
For Version 2.x volume groups, the major number for LVM device files is 128. The volume group
number is encoded into the top twelve bits of the minor number, and the logical volume number
is encoded into the low twelve bits. Logical volume number 0 is reserved for the group file.
NOTE: The most significant bit of the volume group number and logical volume number fields
are reserved and must be zero.
The device number format is subject to change.
LVM Disk Layout
NOTE: This information applies only to disks belonging to Version 1.0 and Version 2.2 (or higher)
volume groups.
There are two kinds of LVM disk layouts, one for boot disks and another for all other LVM disks.
These differ in their data structures. Nonbootable disks have two reserved areas: the physical
volume reserved area (PVRA) and the volume group reserved area (VGRA). Bootable disks have
a PVRA and VGRA, and additional sectors reserved for the boot data reserved area (BDRA) and
boot LIF.
Boot Data Reserved Area
The BDRA contains the information needed to configure the root, primary swap, and dump logical
volumes, and to mount the root file system.
Information about the LVM disk data structures in the BDRA is maintained with the lvlnboot and
lvrmboot commands. The following is a sample output:
# lvlnboot -v
Boot Definitions for Volume Group /dev/vg00:
Physical Volumes belonging in Root Volume Group:
/dev/dsk/c3t0d0 -- Boot Disk
/dev/dsk/c4t0d0 -- Boot Disk
/dev/dsk/c5t0d0
/dev/dsk/c12t0d0 -- Boot Disk
Root: lvol1 on: /dev/dsk/c3t0d0
16 Introduction