To Parallel Server
Oracle Tips by Mike Ault
In a master-master replication situation both
databases are independent entities which maintain a full n-way
replication on all tables. This n-way replication allows both
databases to be used as fully active databases and all changes to
data are copied between both systems. Master-Master n-way
replication is complex to manage and conflict resolution strategies
must be created for all update capable tables. In addition,
master-master replication may require additional bandwidth for the
network that connects the platforms used. One good feature of n-way
or master-master replication is that if it is properly implemented
you can use different system platforms in remote locations.
In a full database copy situation a full hot
backup of the active database is copied from its platform to the
backup site and there it is restored as if from a disaster. A full
database copy provides a backup copy of the database but it is only
current to the copy date. If any activity is allowed against the
database that results form the copy operation, then the databases
are thrown out of sync and a new copy must be made if the databases
are to truly back each other up. The time required for this full
database copy operation can be prohibitive for large databases.
Figure 2 shows an example of this option.
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
instant access to the code depot of Oracle tuning scripts:
Download your Oracle scripts now:
definitive Oracle Script collection for every Oracle professional DBA
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