Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

513Glossary
In Active/Passive disk arrays, a disk can be bound to one particular controller on the disk array or
owned by a controller. The disk can then be accessed using the path through this particular controller.
Also see path and secondary path.
private disk group
A disk group in which the disks are accessed by only one specific host in a cluster. Also see shared
disk group.
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.
RAID
A Redundant Array of Independent Disks (RAID) is a disk array set up with part of the combined
storage capacity used for storing duplicate information about the data stored in that array. This makes
it possible to regenerate the data if a disk failure occurs.
read-writeback mode
A recovery mode in which each read operation recovers plex consistency for the region covered by
the read. Plex consistency is recovered by reading data from blocks of one plex and writing the data to
all other writable plexes.
root configuration
The configuration database for the root disk group. This is special in that it always contains records
for other disk groups, which are used for backup purposes only. It also contains disk records that
define all disk devices on the system.
root disk
The disk containing the root file system. This disk may be under VxVM control.
root file system
The initial file system mounted as part of the UNIX kernel startup sequence.
root partition
The disk region on which the root file system resides.
root volume
The VxVM volume that contains the root file system, if such a volume is designated by the system
configuration.
rootability
The ability to place the root file system and the swap device under VxVM control. The resulting
volumes can then be mirrored to provide redundancy and allow recovery in the event of disk failure.
secondary path
In Active/Passive disk arrays, the paths to a disk other than the primary path are called secondary
paths. A disk is supposed to be accessed only through the primary path until it fails, after which
ownership of the disk is transferred to one of the secondary paths. Also see path and primary path.