NLB Service Monitoring

I looked this up on Microsoft site and it states clearly that Network Load Balancing does not monitor serivce status, it recommends Microsoft Application Center 2000, but it shows a very old application. Is there something newer that will allow me to monitor Service status and route traffic if the service or the port stops responding? NLB is nice and free, but I am starting to not like it when my NLB stops respondings and all the existing connections to the effected node stop responding and stay that way unless I restore the service or restart the server. What software product can I use to stop traffic to a down Logic Server, even if the box is still up?

Thats a good question. In the past, I've used a content services switch to monitor the service and change routing to a different box - this has worked for a number of customers - but the issue has always been that the JDE services do not like anonymous requests "poking" it.

What is really needed is some sort of monitoring system that sits on the application server itself, and publishes a "service port". That way, this service port can be monitored and if it goes down, the client can be directed to a different IP.

I started work on "flipper" a while back - in effect, this would monitor the application server JDE services, and if they did not respond, then "flipper" would turn off its monitor port (port 6900 for example) - and the second part of "flipper" which ran on citrix servers would then change the citrix servers hosts file and point a virtual application servers' machine name to a different IP. Unfortunately I never had time to finish the project.

The real issue, however, is what actually constitutes as a "down" server. Sometimes, the kernels go completely haywire or zombie but the JDENet listener still responds to requests. Not only that, but depending on what release of the service pack you're on, the kernels seem to disappear and reappear without any major issues.

As for Microsoft Network Load Balancing - its totally useless. In effect, it performs "round robin" IP DNS changes - in fact, most "Microsoft clustering" is not much good for failover.

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As for Microsoft Network Load Balancing - its totally useless. In effect, it performs "round robin" IP DNS changes - in fact, most "Microsoft clustering" is not much good for failover.

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I don't know if I would call it totally useless, just a very basic product. It does cause an outage to only impact half of your user base. I agree it quite irritating it will continue to pass request to a dead node. But you can reduce your outage by just going to the Load Balance manager and remove the broken node until you have had time to correct it.

Overall the promise of high availablity is not realized with it. Just a reduced outage. That's why I was going to look at application center or if there was anything newer. If it can notice a non responsive port or stopped service that would be one more step towards real high availaablity and I could start adding hundreds of logic servers, j/k. and leave for a month vacation. Haha.