Veritas Storage Foundation Cross-Platform Data Sharing 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

63Glossary
gap
A disk region that does not contain Veritas Volume Manager objects (subdisks).
HP-UX coexistence label
Data on disk which identifies the disk to the HP volume manager (LVM) as being controlled
by VxVM. The contents of this label are identical to the contents of the VxVM ID block.
mirror
A copy of a volume and its data. There can be several mirrors per volume. The terms mirror
and plex are used synonymously.
node
In the VxVM tree, a node is an element attached to the tree.
In a cluster environment, a node is a host machine in a cluster.
object group
A group of objects of the same type. Each object group has a group icon and a group name.
In VxVM, object groups include disk groups, disks, volumes, controllers, free disk pool
disks, uninitialized disks, and file systems.
object tree
A dynamic hierarchical display of Veritas Volume Manager objects and other objects on the
system. Each node in the tree represents a group of objects of the same type.
platform block
Data placed in sector 0, which contains OS-specific data for a variety of platforms that
require its presence for proper interaction with each of those platforms. The platform
block allows a disk to masquerade as if it was initialized by each of the specific platforms.
plex
A copy of a volume and its data. There can be several plexes per volume. The terms mirror
and plex are used synonymously.
private region
A region of a physical disk used to store private, structured VxVM information. The private
region contains a disk header, a table of contents, and a configuration database. The table
of contents maps the contents of the disk. The disk header contains a disk ID. All data in
the private region is duplicated for extra reliability.
public region
A region of a physical disk managed by VxVM that contains available space and is used for
allocating subdisks.
sector size
Sector size is an attribute of a disk drive (or SCSI LUN for an array-type device), which is set
when the drive is formatted. Sectors are the smallest addressable unit of storage on the
drive, and are the units in which the device performs I/O.
subdisk
A set of contiguous disk blocks that form a logical disk segment. Subdisks are associated
with plexes (mirrors) to form volumes.
uninitialized disks
Disks that are not under VxVM control.