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Richard Niemiec

"Oracle Database 10g Performance Tuning Tips & Techniques"


CONTROL_FILES
The CONTROL_FILES parameter is not required when you create a database. If it is not specified,
Oracle creates one control file in a default location, or if OMF is configured, in the location
specified by either DB_CREATE_FILE_DEST or DB_CREATE_ONLINE_LOG_DEST_n and a
secondary location specified by DB_RECOVERY_FILE DEST. Once the database is created, the
CONTROL_FILES parameter reflects the names of the control file locations if you are using an
SPFILE; if you are using a text initialization parameter file, you must add the location to this file
manually.
However, it is strongly recommended that multiple copies of the control file be created on
separate physical volumes. Control files are so critical to the database integrity and are so small
that at least three multiplexed copies of the control file should be created on separate physical
disks. In addition, the command alter database backup controlfile to trace should be executed
to create a text-format copy of the control file in the event of a major disaster.
The following example specifies three locations for copies of the control file:
CONTROL_FILES = (/u01/oracle10g/test/control01.ctl,
/u03/oracle10g/test/control02.ctl,
/u07/oracle10g/test/control03.ctl)
46 Oracle Database 11g DBA Handbook
DB_BLOCK_SIZE
The parameter DB_BLOCK_SIZE specifies the size of the default Oracle block in the database. At
database creation, the SYSTEM, TEMP, and SYSAUX tablespaces are created with this block size.


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