I have read in documentation that, more than 2 ms away redundancy has to be provided wih cold standby servers. Do you know any way two have warm stand by, do not mind if the configs have to be manually replicated?
All current versions of CCX (5.x and 7.x) only support warm standby in a local LAN deployment.
UCM does support multiple CCX clusters if you configure everything properly. These are entirely separate from every perspective however and in reality is not viable for a fail over solution:
-Requires purchase of a second copy of all licenses (node, agent, etc)
-No replication between clusters: configuration, reporting, scripts, etc all must be configured twice.
-No automatic fail over from one cluster to another. The closest option would be CFB on the CTI Route Points on the first cluster. This does not guarantee a fail over though. Only certain call scenarios would catch the CFB.
-Agents would need to modify postinstall.exe on their PCs manually to log in to the second cluster.
Either do cold standby for now; or, wait until 8.0 for HAoWAN.