April 4, 2007 at 12:38 pm
Hi, I wonder if anyone had ever to do this:
Scenario: You have two clusters each with 2 nodes (4 servers total). Both clusters have identical SQL instances and database and permissions, etc. But they obviously have two different cluster and server names (on the same network). You want to bring down one cluster (both nodes), but you don't want the users to change their ODBC strings. So you think if you make a DNS alias to redirect calls to the first set of servers to the second cluster, you should be okay. But you get a Server not found error.
(I did the same test with two satnd alone SQL and it worked just fine).
Is there a way to make this redirection without having the users to modify their ODBC?
Thanks
A.
April 5, 2007 at 5:42 am
Sounds like a scenario that would work - we do that all the time - move a database from A to B (clustered or not) and change the DNS entry. In fact just yesterday we did it. A little more troubleshooting is probably needed - can you ping the virtual IPs from the clients? Can you ping the DNS entry? Are you sure all the users are using the DNS entry instead of a hardcoded servername or IP?
April 5, 2007 at 5:49 am
Problem solved, that is right, it had nothing to do with cluster. Apparently one of our newbe DBAs just learned how to change tcp/ip ports and had randomly changed them!!
April 5, 2007 at 9:35 am
An interesting twist - the ports mentioned above belong to instances, (3 instnaces on the same server). The General Tab of Client Network utility on the server, TCP port is the default 1433.
When setting up ODBC connection to the server "A", and to any of the instances, there is no need to define port numbers, it dynamicaly does it.
If you modify your local "hosts" file and assign another database server's IP address to server the server "A" (identical in everyway), two things happen:
1- If the database has only one instance, the same ODBC works with no problems
2- If there are more than one instance, then you have define the port number for each instance.
Any idea why?
A.
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