Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

NBU See “Veritas NetBackup (NBU).”
node One of the hosts in a cluster.
object (VxVM) An entity that is defined to and recognized internally by the Veritas Volume
Manager. The VxVM objects include volumes, plexes, subdisks, disks, and disk
groups. There are two types of VxVM disk objects—one for the physical aspect of
the disk and the other for the logical aspect of the disk.
OLTP See “Online Transaction Processing.”
online administration An administrative feature that allows configuration changes without system or
database down time.
OnlineJFS The HP-UX name for the advanced Online Journaled File System, the full-featured
version of the Veritas File System.
Online Transaction
Processing
A type of system designed to support transaction-oriented applications. OLTP
systems are designed to respond immediately to user requests and each request
is considered to be a single transaction. Requests can involve adding, retrieving,
updating or removing data.
paging The transfer of program segments (pages) into and out of memory. Although
paging is the primary mechanism for virtual memory, excessive paging is not
desirable.
parity A calculated value that can be used to reconstruct data after a failure. While data
is being written to a RAID-5 volume, parity is also calculated by performing an
exclusive OR (XOR) procedure on data. The resulting parity is then written to the
volume. If a portion of a RAID-5 volume fails, the data that was on that portion
of the failed volume can be recreated from the remaining data and the parity.
partition The logical areas into which a disk is divided.
persistence Information or state that will survive a system reboot or crash.
petabyte A measure of memory or storage. A petabyte is approximately 1,000 terabytes
(technically, 2 to the 50th power).
plex A duplicate copy of a volume and its data (in the form of an ordered collection of
subdisks). Each plex is one copy of a volume with which the plex is associated.
The terms mirror and plex can be used synonymously.
preallocation Prespecifying space for a file so that disk blocks will physically be part of a file
before they are needed. Enabling an application to preallocate space for a file
guarantees that a specified amount of space will be available for that file, even if
the file system is otherwise out of space.
Quick I/O Quick I/O presents a regular Veritas File System file to an application as a raw
character device. This allows Quick I/O files to take advantage of asynchronous
407Glossary