As the name implies, TAF provides a seamless migration of users??™
sessions from one Oracle instance to another. You can use TAF to mask the failure of
an instance for transparent high availability or to migrate users from an active
instance to a less active one. Figure 11-7 illustrates TAF with Real Application
Clusters.
As shown in this figure, TAF can automatically reconnect clients to another instance
of the database, which provides access to the same database as the original instance.
The high-availability benefits of TAF include the following:
Transparent reconnection
Clients don??™t have to manually reconnect to a surviving instance. You can optimally
reconfigure TAF to preconnect clients to an alternate instance in addition
to their primary instance when they log on. Preconnecting clients to an alternate
instance removes the overhead of establishing a new connection when automatic
Protecting Against System Failure | 273
failover takes place. For systems with a large number of connected clients, this
preconnection avoids the overhead and delays caused by flooding the alternate
instance with a large number of simultaneous connection requests.
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