VERITAS Volume Manager 3.1 Migration Guide

VxVM and LVM
VxVM and LVM—Conceptual Comparison
Chapter 118
VxVM and LVM—Conceptual Comparison
The following section compares the terminology used in LVM and VxVM
at a conceptual level. For more information, refer to the glossary of this
Guide for precise and detailed definitions of these terms.
Table 1-1A Conceptual comparison of LVM and VxVM
LVM Term VxVM Term
LVM VxVM
Both LVM and VxVM enable online disk storage management. They both build
virtual devices, called volumes, on physical disks. Volumes are not limited by the
underlying physical disks, and can include other virtual objects such as mirrors.
Volumes are accessed through the HP-UX file system, a database, or other
applications in the same manner as physical disks would be accessed.
Physical Volume VxVM Disk
An LVM physical volume and a VxVM disk are conceptually the same. A physical
disk is the basic storage device (media) where the data is ultimately stored. You can
access the data on a physical disk by using a device name (devname) to locate the
disk.
In LVM, a disk that has been initialized by LVM becomes known as a physical
volume.
A VxVM disk is one that is placed under the Volume Manager control and is added
to a disk group.
VxVM can place a disk under its control without adding it to a disk group. The
VxVM Storage Administrator shows these disks as “free space pool”.
Logical Volume Volume