I have 3 CAS/HT servers in a CAS array and 4 servers in DAG. The CAS array is load balanced with a hardware load balancer. I have enabled kerberos authentication. When I reboot a CAS server I get prompted for a password. I put in password and Outlook reconnects. If I leave Outlook running and reboot a CAS server again I don't get prompted, Outlook just says disconnected and retrying like it should and will reconnect. If I restarted Outlook and reboot a CAS server I get prompted again. I have turned off autodiscover and that didn't help. I am using cached mode and have disabled that. Nothing seems to work. All servers are Windows 2008 R2 SP1 with Exchange 2010 SP2. Clients are XP and 7 with Outlook 2010 SP1. Any ideas?
I have heard that in some situations, the CAS server may be shown as available to the Load Balancer but is not yet able to service a request.
It is possible that in your case, a shutdown is not being detected fast enough by the load balancer. Based on a friend's recommendation, try reducing the monitoring interval to 5 seconds and a timeout of 16 seconds. This means that the LB would send a TCP probe once every 5 seconds and would wait up to 16 seconds to get some response. If the response does arrive in 16 seconds, the server is marked down. On an F5 BigIP LTM you can set a "time to UP" interval of 90 seconds, this means that the LTM would not try to see if the server is back UP until 90 seconds have passed. This should give the server time to finish booting.
Let us know if that works. I'd like to know if this fixes it myself because I need to do the same for a customer.
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