VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

322 VERITAS Volume Manager Administrator’s Guide
stripe size
The sum of the stripe unit sizes comprising a single stripe across all columns being
striped.
stripe unit
Equally-sized areas that are allocated alternately on thesubdisks (withincolumns) of each
striped plex. In an array, this is a set of logically contiguous blocks that exist on each disk
before allocations are made from the next disk in the array. A stripe unit may also be
referred to as a stripe element.
stripe unit size
The size ofeach stripeunit. The defaultstripe unit size is32 sectors(16K). A stripe unit size
has also historically been referred to as a stripe width.
striping
A layout technique that spreads data across several physical disks using stripes. The data
is allocated alternately to the stripes within the subdisks of each plex.
subdisk
A consecutive setof contiguous diskblocks thatforma logicaldisk segment. Subdiskscan
be associated with plexes to form volumes.
swap area
A disk region used to hold copies of memory pages swapped out by the system pager
process.
swap volume
A VxVM volume that is configured for use as a swap area.
transaction
A set of configuration changes that succeed or fail as a group, rather than individually.
Transactions are used internally to maintain consistent configurations.
volboot file
A small file that is used to locate copies of the rootdg (root disk group) configuration.
The file maylist disks thatcontain configuration copies instandardlocations, and can also
contain direct pointers to configuration copy locations. A rootdg that contains only
simple disks requires entries for at least some of those disks in the volboot file so that
vxconfigd can configurethe disk group. The volboot fileis storedin a system-dependent
location.