Veritas Storage Foundation™ for Oracle 5.0.1 Administrator's Guide

By default, OMF datafiles are created with auto-extend capability. This attribute
reduces capacity planning associated with maintaining existing databases and
implementing new applications. Due to disk fragmentation that occurs as the
tablespace grows over time, database administrators have been somewhat cautious
when considering auto-extensible tablespaces. Oracle Disk Manager eliminates
this concern.
When Oracle Disk Manager is used in conjunction with OMF, special care is given
within Veritas Extension for Disk Manager to ensure that contiguous disk space
is allocated to datafiles, including space allocated to a tablespace when it is
auto-extended. The table and index scan throughput does not decay as the
tablespace grows.
How Oracle Disk Manager works with Oracle Managed Files
The following example illustrates the relationship between Oracle Disk Manager
and Oracle Managed Files (OMF). The example shows the init.ora contents and
the command for starting the database instance. To simplify Oracle UNDO
management, the new Oracle9i or later init.ora parameter UNDO_MANAGEMENT is
set to AUTO. This is known as System-Managed Undo.
Note: Before building an OMF database, you need the appropriate init.ora default
values. These values control the location of the SYSTEM tablespace, online redo
logs, and control files after the CREATE DATABASE statement is executed.
$ cat initPROD.ora
UNDO_MANAGEMENT = AUTO
DB_CREATE_FILE_DEST = '/PROD'
DB_CREATE_ONLINE_LOG_DEST_1 = '/PROD'
db_block_size = 4096
db_name = PROD
$ sqlplus /nolog
SQL> connect / as sysdba
SQL> startup nomount pfile= initPROD.ora
The Oracle instance starts.
Total System Global Area 93094616 bytes
Fixed Size 279256 bytes
Variable Size 41943040 bytes
Database Buffers 50331648 bytes
Redo Buffers 540672 bytes
123Using Veritas Extension for Oracle Disk Manager
About Oracle Disk Manager and Oracle Managed Files