VERITAS Volume Manager 4.1 Administrator's Guide

Glossary
associate
Glossary430
associate The process of establishing a
relationship between VxVM objects; for
example, a subdisk that has been created
and defined as having a starting point
within a plex is referred to as being
associated with that plex.
associated plex A plex associated with a
volume.
associated subdisk A subdisk associated
with a plex.
atomic operation An operation that either
succeeds completely or fails and leaves
everything as it was before the operation
was started. If the operation succeeds, all
aspects of the operation take effect at once
and the intermediate states of change are
invisible. If any aspect of the operation fails,
then the operation aborts without leaving
partial changes.
In a cluster, an atomic operation takes place
either on all nodes or not at all.
attached A state in which a VxVM object is
both associated with another object and
enabled for use.
block The minimum unit of data transfer to
or from a disk or array.
boot disk A disk that is used for the
purpose of booting a system.
clean node shutdown The ability of a node
to leave a cluster gracefully when all access
to shared volumes has ceased.
cluster A set of hosts (each termed a node)
that share a set of disks.
cluster manager An externally-provided
daemon that runs on each node in a cluster.
The cluster managers on each node
communicate with each other and inform
VxVM of changes in cluster membership.
cluster-shareable disk group A disk
group in which access to the disks is shared
by multiple hosts (also referred to as a
shared disk group). Also see private disk
group.
column A set of one or more subdisks
within a striped plex. Striping is achieved by
allocating data alternately and evenly across
the columns within a plex.
concatenation A layout style characterized
by subdisks that are arranged sequentially
and contiguously.
configuration copy A single copy of a
configuration database.
configuration database A set of records
containing detailed information on existing
VxVM objects (such as disk and volume
attributes).
data change object (DCO) A VxVM object
that is used to manage information about
the FastResync maps in the DCO volume.
Both a DCO object and a DCO volume must
be associated with a volume to implement
Persistent FastResync on that volume.
data stripe This represents the usable data
portion of a stripe and is equal to the stripe
minus the parity region.
DCO volume A special volume that is used
to hold Persistent FastResync change maps.