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Porting
To Parallel Server
Oracle Tips by Mike Ault |
Other Options
Before we get into parallel server what are
other possible options to allow for high availability and limited
downtime for a production system? Essentially there are three other
options: standby database, master-master replication and full
database copies.
Standby Database
With the standby database option you maintain
two copies of the database, one an active database, the other a full
copy of the active database left in recovery mode. The archived redo
log files are copied from the active database to the standby
database platform and are applied as they are generated to the
standby database. If the active database becomes corrupted, the
worse case is that a singe redo log worth of transactions are lost,
this suggests that a small redo log size should be used in the
standby database option. In Oracle version 7 the standby database is
not accessible until the final archive log is applied and it is
opened for use. In Oracle version 8 the standby database can be used
in a read-only mode even while it is in recovery mode. Figure 1
demonstrates the standby database option.
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For more information on this topic, I recommend Don
Burleson's latest book "Oracle
Tuning: The Definitive Reference".
You can buy it direct from the publisher for 50%-off and get
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