VERITAS Storage Foundation 4.1 Oracle Administrator's Guide

Prerelease 8 September 2005, 8:55am
530 VERITAS Storage Foundation for Oracle Administrator’s Guide
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.
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 I/O and direct I/O to and from the
disk device, as well as bypassing the UNIX single-writer lock behavior for most file system files.
Quick I/O file
A regular UNIX file that is accessed using the Quick I/O naming extension (::cdev:vxfs:).