HP-UX System Administrator's Guide: Logical Volume Management (5900-3028, March 2013)

Physical Volume Names
Physical volumes are identified by their device file names, as follows:
Table 1 Physical Volume Naming Conventions
Type of DeviceDevice File Name
Persistent block device file/dev/disk/diskn
Persistent block device file, partition 2/dev/disk/diskn_p2
Persistent character device file/dev/rdisk/diskn
Persistent character device file, partition 2/dev/rdisk/diskn_p2
Legacy block device file/dev/dsk/cntndn
Legacy block device file, partition 2/dev/dsk/cntndns2
Legacy character device file/dev/rdsk/cntndn
Legacy character device file, partition 2/dev/rdsk/cntndns2
Cluster block device file/dev/cdisk/diskn
Cluster character device file/dev/rcdisk/diskn
Each disk has a block device file and a character or raw device file, the latter identified by the r.
Which name you use depends on what task you are doing with the disk.
For the boot disk on HP Integrity servers, make sure to use the device files with the _p2 suffix or
s2 suffix, because they represent the HP-UX partition on the boot disk. On HP 9000 servers, use
the device file without a partition number.
Use a physical volume’s raw device file for the following tasks only:
• Preparing a physical volume for LVM using the pvcreate command. Here you use the device
file for the disk; for example, /dev/rdisk/disk14. (The absence of a partition suffix
indicates that you are referring to the entire disk.)
• Removing LVM information from a physical volume using the pvremove command.
• Restoring your volume group configuration using the vgcfgrestore command.
• Performing a consistency check on a physical volume using the pvck command.
• Modifying the volume group identifier on a physical volume using the vgchgid command.
• Changing the disk type of a physical volume using the vgmodify command.
For all other tasks, use the block device file. For example, when you add a physical volume to a
volume group using the vgextend command, you use the disk’s block device file for the disk,
such as /dev/disk/disk14.
All disk device files are created automatically when a new disk is discovered. For more information,
see insf(1M).
Volume Group Names
Each volume group must have a unique name, up to 255 characters. For example, typical volume
group names are vg01, vgroot, or vg_sales. Although the name does not need to start with
vg, HP recommends using this prefix. By default, HP SMH uses the names of the form /dev/vgnn.
The number nn starts at 00 and is incremented in the order that volume groups are created. By
default, the root volume group is vg00.
14 Introduction