Veritas Volume Manager 5.0.1 Migration Guide, HP-UX 11i v3, First Edition, November 2009

Table 1-1
A conceptual comparison of LVM and VxVM (continued)
DescriptionVxVM termLVM term
LVM volume groups are conceptually
similar to VxVM disk groups.
An LVM volume group is the collective
identity of a set of physical volumes,
which provide disk storage for the
logical volumes.
A VxVM disk group is a collection of
VxVM disks that share a common
configuration. A configuration is a set
of records with detailed information
about related VxVM objects, their
attributes, and their associations.
Disk groupVolume group
User data is contained in physical
extents in LVM and subdisks in VxVM.
The LVM physical extents are of a
fixed length. LVM allocates space in
terms of a physical extent which is a
set of physical disk blocks on a
physical volume. The extent size must
be the same for all physical volumes
within a volume group. The extent
size is usually 4 MB.
VxVM allocates disk space in term of
subdisks which is a set of physical disk
blocks representing a specific
contiguous portion of a VxVM disk
and is of arbitrary size.
SubdiskPhysical extent
LVM metadata and the Private Region
are similar conceptually.
In LVM, metadata is stored in a
reserved area in the disk.
In VxVM, the private region of a disk
contains various on-disk structures
that the Volume Manager uses for
various internal purposes. Private
regions can also contain copies of a
disk group’s configuration, and copies
of the disk group’s kernel log.
Private regionLVM metadata
15VxVM and LVM
VxVM and LVM—conceptual comparison