Hi,
I have been playing around with NLB and noticed some unexpected behaviour.
Scenario: I have 2 NLB hosts load balancing 2 Web Servers e.g. Server1 running NLB and Apache1 and Server 2 running NLB and Apache2. Single affinity enabled with a timeout of 5 minutes.
Issue / understanding 1: If I hit Server1 then I only ever see Apache1 instance. I assume that this is because (a) the Affinity is between the Client and NLB and not the Client and the Host and (b) once the request hits Server1 it only uses the Apache instance on Server1...... (I expected NLB on Server1 to be able to see both Apache instances) Is this understanding correct?
Issue / understanding 2: If I stop Apache1 on this server (reflective of a failure of the Apache instance) then I just get blank pages as NLB is running and accepting requests. It seems to be unable to detect there is an issue with the service it is load balancing. Is this correct?
If these are both right then how is NLB fault tolerant under Affinity. Surely once Apache fails on Server1 almost 50% of all requests will continue to fail unless NLB is stopped on that host.
Sorry but I appear to have either a misunderstanding of how NLB works or my environment is not configured correctly.
Thanks,
Eddie