HP-UX System Administrator's Guide: Overview HP-UX 11i v3 (B3921-90011, September 2010)

Volume managers allow you to group collections of physical storage (usually disk drives) and
then divide the collections into logical entities called logical volumes if you are using the HP
Logical Volume Manager, or simply volumes if you are using the VERITAS Volume Manager.
HP-UX 11i version 3 supports the following volume managers:
LVM The Logical Volume Manager (LVM) is detailed in HP-UX System Administrator’s Guide:
Logical Volume Management. LVM is the default volume manager for HP-UX 11i.
VxVM The VERITAS Volume Manager (VxVM) has many features, some of which are not
available with LVM or MirrorDisk/UX (the companion product to LVM that allows you
to mirror data onto multiple physical disks).
The version of VxVM that ships with HP-UX is a base version containing a subset of the
features offered in the full version (which requires an additional license). For complete
information about which features are included with the base version and the full version
of VxVM see the VERITAS Volume Manager Releases Notes corresponding to the version
of the VERITAS Volume Manager you are using.
Both volume managers can co-exist on a server. Each volume manager keeps track of which
disks it is controlling and any given physical disk can only be a controlled by one volume manager
at a time. The utility vxvmconvert can convert an LVM volume group to a VxVM disk group
if you want to migrate a disk from LVM to VxVM for greater configuration flexibility.
Volume Management Tasks
The specific volume management tasks you will need to perform will vary slightly depending
on which volume manager you choose. For tasks that are common to both LVM and the VERITAS
Volume Manager, the specific commands or interfaces you will need to use will also vary
depending on which volume manager you are using.
Common volume management tasks include:
• Volume Group / Disk Group Tasks
— Creating volume groups (from collections of physical disks)
— Adding physical disk drives to an existing volume group
— Removing physical disk drives from a volume group
— Mirroring data
• Logical Volume / Volume Tasks
— Creating volumes
— Removing volumes
— Resizing volumes (and, if appropriate, the file systems within them)
In both LVM and the VERITAS Volume Manager, one volume group is treated special: the root
volume group. This refers to the volume group that contains the kernel file that is used for booting
the system. It is also where the root file system, the file system containing the root directory (“/”),
resides. The specifics of how the root volume group is special (how it differs from other volume
groups) varies depending on which volume manager you are using. Refer to the documentation
for the volume manager you are using for specific information on the differences.
Performance Monitoring Tools
There are many tools available to help you monitor performance of HP-UX based servers,
networks, and applications. Some of these tools are included with HP-UX, some are downloadable
from hp.com, and some are commercial products from HP or other companies. This section
discusses a few of these tools.
Tools for Monitoring the Performance of a Server
There are several applications you can use to monitor the performance of an HP-UX based server:
102 System Administration Tools