CAD with High Availability

[Keith Joel]

Hello All,

     I'm in the process of implementing a CCX 8.X deployment with high availability.  My question is, similar to phones registering to Call Manager subscribers rather than the publisher, should CAD be talking to the CCX subscriber rather than the publisher?  I ran the configuration MSI for CAD and CSD but CAD is till trying to contact the pub first and sub second even though I've entered the IP address for the subscriber.  Or, should it simply be talking to the publisher and failing back to the subscriber as necessary?

Thanks for your time,

Keith

[Jonathan Schulenberg · Accepted solution]

CCX does not follow the same deployment roles that UCM does. Only one node is ever in service at a time. CAD and all other services/call processing is done on whichever came into service first. If that server fails or looses connectivity, all of the services and the database will fail over to the second node. This is a warm standby model, not hot as UCM is.

[Anthony Holloway]

One interesting behavior I found out recently:  CAD will always attempt the pub first, even if the sub has mastership or the pub is powered down.

In the case of the mastership residing with the sub, things kind of work as normal, or like the SRND says they should.  HTTP triggers even auto redirect.

However, in the case of the pub being powered down (crashed, on fire, flood, whatever), CAD will wait a timeout period for every action it performs, trying to contact the pub, and before going to the sub.  It's over a minute to login, around 15 seconds for CTI device control actions, and other weird timeout behaviors.

I was told by TAC to just run postinstall on the client, and remove the pub address, and put the sub address in the primary slot, well, CAD auto updates these values when it connects to UCCX, so that didn't help.  I even tried re-running the client config tool, and using the sub address, but it failed to let me do it.

[Keith Joel]

Perfect thanks guys.  The warm standby explanation was exactly what I needed.