Network load balancing test case

[KT Ho]

I have setup two Windows Server 2003 Servers with network load balance.
Apache software (service mode) was installed for the two servers. When
Apache service started in both servers, NLB is no problem. But when Apache
services was down in one of the server, I experienced the traffic still
share for both servers. However, client will hit 50% failure. Can anyone can
help, whether it is a right behavior or not?

[Fredrik Arenhag]

This is a correct behavior since the NLB-services have no knowledge of
the other services running on the hosts. NLB only takes general system
status into consideration when the hosts are to decide if they shall
respond to the request or not.

You could extend your environment with a script that regularly polls the
services and if they go offline the script could issue a command to the
NLB-cluster which would set the faulting host offline.

Kind regards,
Fredrik Arenhag

Post by KT Ho
I have setup two Windows Server 2003 Servers with network load balance.
Apache software (service mode) was installed for the two servers. When
Apache service started in both servers, NLB is no problem. But when Apache
services was down in one of the server, I experienced the traffic still
share for both servers. However, client will hit 50% failure. Can anyone can
help, whether it is a right behavior or not?

[Tonny Jørgensen]

Post by Fredrik Arenhag
This is a correct behavior since the NLB-services have no knowledge of
the other services running on the hosts. NLB only takes general system
status into consideration when the hosts are to decide if they shall
respond to the request or not.
You could extend your environment with a script that regularly polls the
services and if they go offline the script could issue a command to the
NLB-cluster which would set the faulting host offline.
Kind regards,
Fredrik Arenhag

Has anyone managed to make such a script ? I have the exact same
situation here with 2 iis webservers running in nlb. When one of the IIS
servers crashed and the server still is alive 50% of all web requests is
sent to the crashed iis webserver.

How could one in a script poll the iis status and stop / start the nlb
service ?

- Tonny