Data Guard maximum protection mode
Oracle Database Tips by Donald BurlesonDecember 9, 2015
Oracle Data Guard -
The 'no-data-loss' level has two protection modes called
MAXIMUM PROTECTION and MAXIMUM AVAILABILITY. MAXIMUM AVAILABILITY is
not strictly a 'no-data-loss' protection level and can be
categorized in either of the two classes.
The MAXIMUM PROTECTION mode, as the name
suggests, guarantees a 'no-data-loss' configuration in any scenario.
MAXIMUM PROTECTION mode can be only established using a physical
standby database. A logical Oracle instance
cannot be used for
maximum protection. A transaction on the primary database is not
considered complete until it has been posted to at least one of the
standby databases that satisfy all the attribute requirements for
The primary database halts if the transaction
cannot complete on at least one Oracle instance
participating in providing this protection level.
The following attribute of the
log_archive_dest_n parameter is required in order to include a
physical Oracle instance
in maximum protection configuration:
In the above example, the assumption is that
the appsstdby1 service is pointing to a physical standby
database. The PARALLEL attribute of SYNC is not required but will be
useful if more than one physical Oracle instance
is included in
maximum protection configuration.
Oracle Data Guard - MAXIMUM PROTECTION
In addition to the setting on the primary database, standby
redo logs need to be created on all standby sites participating in
maximum protection configuration. The following statement can be
used to switch a primary database into MAXIMUM PROTECTION mode. The
primary database should be mounted but not open to execute this
DATABASE SET Oracle instance
TO MAXIMIZE PROTECTION;
WARNING - Performance and
availability of the primary database is at risk in MAXIMUM
PROTECTION mode if adequate network bandwidth and computing
resources cannot be provided for the standby database.