Non-Redundant GTM Pair and DNS
Forgive me if this is a stupid question, but after reading and re-reading the manuals and searching through the forums I'm still stumped.
I currently have four BIGIP 3900 units, two each at separate sites configured as a HA LTM pairs and one unit at each site has been licensed with a GTM module (I'm well-aware of the specific advice against asynchronously licensed HA pairs). The GTMs have been configured as a ConfigSync group.
The objective is to have wideip requests routed to the topologically closest resource to the requester and also to fail over to the remote site. I've managed to configure two separate wideips to this end and both are working as expected, but I've hit a stumbling block in that the SOA for the delegated subdomain can specify only a single server. I understand that normally this wouldn't be a problem for a HA GTM pair as the SOA would refer to a floating IP address, but in this scenario where the GTM's are not in a HA pair, it's proving to be a single failure point.
Does anyone have a suggestion how it may be possible to work around this problem or should I just accept that this is an unavoidable limitation of the design?