During the PoC of the IBM SVC Stretched Cluster for Oracle RAC, some of the tests were to simulate Oracle RAC node failure or entire site failure.
We had configured Oracle SCAN IP on the cluster, this meant that the clients would be evenly balanced between the two nodes of the Oracle RAC cluster.
We also configured Oracle TAF(Transparent Application Failover).
FAILOVER CONCEPTS from
http://www.oracle.com/technetwork/database/features/oci/taf-10-133239.pdf
Failover allows a database to recover on another system within a cluster. Figure illustrates a typical database cluster configuration. Although the example shows a two-system cluster, larger clusters can be constructed. In a cold failover configuration, only one active instance can mount the database at a time. With Oracle Real Application Clusters, multiple instances can mount the database, speeding recovery from failures.
The failure of one instance will be detected by the surviving instances, which will assume the workload of the failed instance. Clients connected to the failed instance will migrate to a surviving instance. The mechanics of this migration will depend upon the cluster configuration. Transparent Application Failover feature will automatically reconnect client sessions to the database and minimize disruption to end-user applications.
Here is the tnsnames.ora file with TAF configured that we used for the PoC
On the client machine
We had configured Oracle SCAN IP on the cluster, this meant that the clients would be evenly balanced between the two nodes of the Oracle RAC cluster.
We also configured Oracle TAF(Transparent Application Failover).
FAILOVER CONCEPTS from
http://www.oracle.com/technetwork/database/features/oci/taf-10-133239.pdf
Failover allows a database to recover on another system within a cluster. Figure illustrates a typical database cluster configuration. Although the example shows a two-system cluster, larger clusters can be constructed. In a cold failover configuration, only one active instance can mount the database at a time. With Oracle Real Application Clusters, multiple instances can mount the database, speeding recovery from failures.
The failure of one instance will be detected by the surviving instances, which will assume the workload of the failed instance. Clients connected to the failed instance will migrate to a surviving instance. The mechanics of this migration will depend upon the cluster configuration. Transparent Application Failover feature will automatically reconnect client sessions to the database and minimize disruption to end-user applications.
Here is the tnsnames.ora file with TAF configured that we used for the PoC
On the client machine
| -sh-4.1$ pwd /home/oracle -sh-4.1$ cat tnsnames.ora # tnsnames.ora Network Configuration File: /u01/app/ora11/product/11.2.0/dbhome_1/network/admin/tnsnames.ora # Generated by Oracle configuration tools. svccon = (description= (address=(protocol=tcp)(host=192.168.45.244)(port=1521)) (address=(protocol=tcp)(host=192.168.45.245)(port=1521)) (load_balance=yes) (connect_data = (server = dedicated) (service_name=svcdb) (failover_mode = (type=select) (method=basic) (retries=180) (delay=5) ) ) ) |
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