With 7.6.x move to use global search, FTS has become a key component of ITSM cornerstone functionality.
FTS certainly puts a damper on seemless failover capabilities.
We are told by support even with a server group configuration we will need to shutdown all AR services, update AR and ARMONITOR CONFIGS, bring up rimary for FTS, and exec re-index (which could take several hours)!
See KA 363429
Customers rely on global search and its accuracy - it is not acceptable for this functionality to be drastically impaired for a lengthy time after a failover to an alternate location.
A primary and secondary index sync is at the very least needed to help in the failover process.