Local Director unable to detect a failed web site

[john.yeung]

Hi all,

I have configured the local director to load balance several web sites on two real servers. One of these sites is required to be configured in backup mode.

For some reason the local director is unable to detect the site has gone down (by stopping the site to update the web content), therefore not directing requests to the backup real server.

I am using IIS 5.0, since its quite popular out there, has anyone experienced a similar situation and if so, how did you resolve it?

thanks

[mike.pacheco]

Your problem is based in the Operating system, not the Local Director. The LD is a layer 3 device. Microsoft put their application architecture together different from the Unix world, ie: Any ip address bound to a MS box is answered for by the OS - not the application (IIS in this case) If IIS is hosed up the OS will still answer for the IP you have bound to the NIC of the OS - the OS does not care at layer 3 that you want a higher level reply - LD does its availability checking at Layer 3 - the OS layer for MS. In the Unix world when an application is bound to a port - ie: Apache to port 80, then the apache deamon answers for that ip/port - not the OS - Apache panics and it will not respond at Layer 3 - the OS could be fine, but the LD will know that ip/port is not responding and will take the appropriate actions by your LD config.

Check out the httpprobe feature of the LD - it lets you test for a file in a URL inside the LD.

Cheers