we host 4 web servers behind a shared load balancer. We don't have control over this Citrix NetScaler load balancer. We submit tickets to make changes as needed.
Recently, one of the web servers started to have issues like slow backend response times. Troubleshooting takes longer, therefore we wanted to have logic so if a request is not served within a certain threshold (let's say 15 secs) consider the server as down and forward requests to other servers from that time.
We contacted the hosting company and asked them whether it is possible to do this on their end. They say, it is provided via SNMP but they do not support SNMP on Shared load balancers.
We run the websites on IIS 8.5 (Server OS 2012 R2). We would like to know if any other IIS way of implementing this health check mechanism on our end exists?