Remove load balancing...

Question

Oracle 10gR2 RHEL 4 AS 64bit
I wanted to know is there a way to remove load balancing in RAC? Would I just set the LOAD_BALANCE parameter to OFF in the TNSnames.ora file? Would that take care of it? The problem is occurring because developers are trying to upload images into the database (using jumploader) and the file is stored on the first node. What happens is during the upload a procedure searches for the file on the second node (when it is actually on the first node) and then an error is returned. Below are my current TNS entries:
PROD =
(DESCRIPTION =
(LOAD_BALANCE = ON)
(FAILOVER = ON)
(ADDRESS = (PROTOCOL = TCP)(HOST = node1-vip)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = node2-vip)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = TAF)
(FAILOVER_MODE =
(TYPE = SELECT)
(METHOD = BASIC)
(RETRIES = 180)
(DELAY = 1)
TAF =
(DESCRIPTION =
(LOAD_BALANCE = ON)
(FAILOVER = ON)
(ADDRESS = (PROTOCOL = TCP)(HOST = node1-vip)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = node2-vip)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = TAF)
PROD2 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = node2-vip)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = PROD)
(INSTANCE_NAME = PROD2)
PROD1 =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = node1-vip)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = PROD)
(INSTANCE_NAME = PROD1)
)

Answer 1

In this case, changing the tnsnames.ora file alone won't do it. RAC has two independent load balancing sides, client side (tnsnames level) and server side (listener level). The client side is simply a random (yep, random) picking of a listener on an instance to go to. On the server side, however, a given listener can then hand that connection off to another listener on a less loaded machine. Even if you connect via tnsnames to a specific instance, you may be connected to another machine.
Your best bet would be to use services, you can create a service in the cluster that can connect to a specific node with a different service name than "standard" connection. I have used this for reporting instances on a specific node cluster. You then create a new tnsnames alias to point to that new server. Note. If you use the SERVICE_NAMES parameter within your database this will not work, as anything pointed to by it will override the service names.
An alternate idea would be to nfs mount your filesystem that contains the pictures to each of your remaining rac nodes.
Cheers
Jay Caviness
http://www.grumpy-dba.com