VERITAS Storage Foundation 4.1 Oracle Administrator's Guide

Glossary 523
Prerelease 8 September 2005, 8:55am
control file
An Oracle control file specifies the physical structure of an Oracle database, including such things
as the database name, names and locations of the datafiles and redo log files, and the timestamp of
when the database was created. When you start an Oracle database, the control file is used to
identify the database instance name redo log files that must be opened for transaction recording and
recovery and datafiles where data is stored.
copy-on-write
A technique for preserving the original of some data. As data is modified by a write operation, the
original copy of data is copied.
Applicable to Storage Checkpoint technology, where original data, at the time of the Storage
Checkpoint, must be copied from the file system to the Storage Checkpoint when it is to be
overwritten. This preserves the frozen image of the file system in the Storage Checkpoint.
data block
A logical database data storage unit. Blocks contain the actual data. When a database is created, a
data block size is specified. The database then uses and allocates database space in data blocks.
database
A database is a collection of information that is organized in a structured fashion. Two examples of
databases are Relational Databases (such as Oracle, Sybase, or DB2), where data is stored in tables
and generally accessed by one or more keys and Flat File Databases, where data is not generally
broken up into tables and relationships. Databases generally provide tools and/or interfaces to
retrieve data.
VxDBA maintains a flat file database of information on the available Oracle instances on a system.
datafile
A physical database attribute that contains database data. An Oracle datafile can only be associated
with a single database. One or more datafiles form a logical database storage unit called a
tablespace.
Decision Support Systems
Decision Support Systems (DSS) are computer-based systems used to model, identify, and solve
problems, and make decisions.
defragmentation
The act of reorganizing data to reduce fragmentation. Data in file systems become fragmented over
time.