Proxy Monitoring

We have tried to monitor our proxy servers a few different ways. The first way was to monitor going out to 4 different websites, and had it set to at least 2 up before the monitor marked the proxy server down. This didn't work, as we ran into a situation where 3 of the 4 were down at the same time. Then we set the monitors to look at our two internet facing interfaces with at least 1 up before marking it down. This has worked great for us for some time, but we ran into a situation where one of the proxies just crashed. Since the LTM still seen that proxy as up because the monitor looks at the routers instead, it continued to send traffic to it. We have two geographically separated Data Centers, our users are split between the two for internet access. Marking one proxy down we have no issues, if both are marked down the GTMs will fail everyone over to the other data center. This does take some time, and some timeout errors in the process of moving them.

 

I am looking for a better way to do the monitoring. If I put TCP on the monitor, then I feel that I would have to change to all having to be up. But if I lose just one proxy in the data center, then I fail over to the other data center, and not really using my redundancy the way that it is designed. Any thoughts or suggestions would be great appreciated. If you need more information please let me know.