Example Tnsnames for Load Balancing

Konfigurasi untuk LOAD BALANCING Connection   (tnsnames.ora)

SERVICE_NAME=
(DESCRIPTION=
(LOAD_BALANCE=on)
(FAILOVER=on)
(ADDRESS_LIST=
(SOURCE_ROUTE=yes)
(ADDRESS=(PROTOCOL=tcp)(HOST=host1)(PORT=1630))
(ADDRESS=(PROTOCOL=tcp)(HOST=host2)(PORT=1521)))
(ADDRESS_LIST=
(SOURCE_ROUTE=yes)
(ADDRESS=(PROTOCOL=tcp)(HOST=host3)(port=1630))
(ADDRESS=(PROTOCOL=tcp)(HOST=host4)(port=1521)))
(CONNECT_DATA=(SERVICE_NAME=sales.us.acme.com)))

Explanation:

1. The client is instructed to pick an ADDRESS_LIST at random and to failover to the
other if the chosen ADDRESS_LIST fails. This is indicated by the LOAD_BALANCE
and FAILOVER parameters being set to on.
2. When an ADDRESS_LIST is chosen, the client first connects to the Oracle
Connection Manager, using the Oracle Connection Manager protocol address that
uses port 1630 indicated for the ADDRESS_LIST.
3. The Oracle Connection Manager then connects to the database service, using the
protocol address indicated for the ADDRESS_LIST.