Re: Questions re LOCAL_LISTENER & REMOTE_LISTENER

William Wagman schrieb:

> 
> And the mirror image on node 2. This is puzzling to me as the
> tnsnames.ora listed in example 9.1 of the Real Application Clusters
> Installation guide looks like the one I currently have. I think my lack
> of understanding has to do with how the local and remote listener
> parameters function so if someone could help me in my understanding I
> would be most grateful.

you're right, LOCAL_LISTENER on each node should point to the listener on that node. REMOTE_LISTENER should point to all listeners on all nodes if you want server side load balancing, otherwise don't set REMOTE_LISTENER.

so to make your configuration right, you should setup it like this:

node1:

LOCAL_LISTENER_NODE1 =
  (ADDRESS_LIST =
    (ADDRESS =
(PROTOCOL = TCP)
(HOST = node1-vip)
(PORT = 1521)

    )
  )
REMOTE_LISTENERS =
  (ADDRESS_LIST =
    (ADDRESS =
(PROTOCOL = TCP)
(HOST = node1-vip)
(PORT = 1521)

    )
    (ADDRESS =
(PROTOCOL = TCP)
(HOST = node2-vip)
(PORT = 1521)

    )
  )

LOCAL_LISTENER=LOCAL_LISTENER_NODE1
REMOTE_LISTENER=REMOTE_LISTENERS node2:

LOCAL_LISTENER_NODE2 =
  (ADDRESS_LIST =
    (ADDRESS =
(PROTOCOL = TCP)
(HOST = node2-vip)
(PORT = 1521)

    )
  )
REMOTE_LISTENERS =
  (ADDRESS_LIST =
    (ADDRESS =
(PROTOCOL = TCP)
(HOST = node1-vip)
(PORT = 1521)

    )
    (ADDRESS =
(PROTOCOL = TCP)
(HOST = node2-vip)
(PORT = 1521)

    )
  )

LOCAL_LISTENER=LOCAL_LISTENER_NODE2
REMOTE_LISTENER=REMOTE_LISTENERS on a 2-node cluster your REMOTE_LISTENER can point to a single listener but i find it easier to keep REMOTE_LISTENER identical on all nodes.

the purpose of REMOTE_LISTENER is to connect all instances with all listeners so the instances can propagate their load balance advisories to all listeners. if you connect to a listener, this listener uses the advisories to decide who should service your connect. if the listener decides its local instance(s) are least loaded and should service your connect it passes your connect to the local instance. if the node you connected to is overloaded, the listener can use TNS redirect to redirect your connect a less loaded instance.

regards,
-ap

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