Two ways to configure Oracle SQL*Net on the client (the TNSNAMES.ORA file) are shown below. The client reconnection time to the surviving instance is not influenced by the method used to configure Oracle SQL*Net.
Configure the same "connect string" for multiple instances to run on different hosts with the same ORACLE SID.
ora = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP) (HOST = erlan) (PORT = 1526) <- instance 1 ) (CONNECT_DATA= (SID=ora)) ) (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP) (HOST = weibull) (PORT = 1526) <- instance 2 ) (CONNECT_DATA= (SID=ora)) ) ) |
Configure the same "connect string" for instances to run on different hosts with different ORACLE SIDs.
ora = (DESCRIPTION_LIST = (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP) (HOST = erlang) (PORT = 1526)) (CONNECT_DATA = (SID = ora)(GLOBAL_NAME = ora)) ) (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP) (HOST = weibull) (PORT = 1526)) (CONNECT_DATA = (SID = ora1)(GLOBAL_NAME = ora)) ) ) |
This configuration has listeners running for each of the instances.