Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

snapped volume A volume whose exact image has been used to create a snapshot volume.
snapshot A point-in-time image of a volume or file system that can be used as a backup.
snapshot file system An exact copy of a mounted file system, at a specific point in time, that is used
for online backup. A snapshot file system is not persistent and it will not survive
a crash or reboot of the system.
snapshot volume An exact copy of a volume, at a specific point in time. The snapshot is created
based on disk mirroring and is used for online backup purposes.
spanning A layout technique that permits a volume (and its file system or database) too
large to fit on a single disk to distribute its data across multiple disks or volumes.
Storage Checkpoint An efficient snapshot technology for creating a point-in-time image of a currently
mounted VxFS file system. A Storage Checkpoint presents a consistent,
point-in-time view of the file system by identifying and maintaining modified file
system blocks.
storage class Set of volumes with the same volume tag.
Storage Rollback On-disk restore capability for faster recovery from logical errors, such as
accidentally deleting a file. Because each Storage Checkpoint is a point-in-time
image of a file system, Storage Rollback simply restores or rolls back a file or
entire file system to a Storage Checkpoint.
stripe A set of stripe units that occupy the same positions across a series of columns in
a multi-disk layout.
stripe unit Equally sized areas that are allocated alternately on the subdisks (within columns)
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.
stripe unit size The size of each stripe unit. The default stripe unit size for VxVM is 32 sectors
(16K). For RAID 0 stripping, the stripe unit size is 128 sectors (64K). For VxVM
RAID 5, the stripe unit size is 32 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 set of contiguous disk blocks that form a logical disk segment.
Subdisks can be associated with plexes to form volumes.
superuser A user with unlimited access privileges who can perform any and all operations
on a computer. In UNIX, this user may also be referred to as the “root” user. On
Windows/NT, it is the “Administrator.”
System Global Area The area of memory used for database information shared by all database users.
Each SGA contains the data and control information for a single Oracle instance.
409Glossary