Troubleshooting

From LB Wiki

These are the most common issues that come up with load balancing:

• Servers are up, but no response when I go to the VIP
  • Possible issues
    • The default gateway of the server is not the load balancer
    • The health checking is insufficient of detecting an actual down situation
    • You're running transparent mode, and the client is on the same subnet as the real server

• Where are my @#$%ing logs!?!?!

Your web server's logs show all connections as coming from the load balancer, and the actual IP addresses are no where in sight.

This is known as non-transparency. The load balancer acts as a proxy for client connections.

The good news is it's easy to fix. Either turn on persistence and change the default gateway, or use an HTTP header and Apache configuration or ISAPI filter to fill the logs in correctly. The bad news is, there's no way to retrieve the lost logs. No load balancer keeps a log of all incoming connections. They are lost for good.

Here are various articles for troubleshooting a server load balancer installation.

• Virtual down, server up: When the Virtual Service (VIP) not responding, but the server is up