GTM resolution when all pools are unavailable?

What should I expect the GTM to do with DNS when all pool members are unavailable (marked down by health monitors, or disabled)? I'm currently seeing some odd behavior with all pool members down - the GTM is returning 4 IP addresses, 2 for each datacenter, and ignoring any Topology/Global availability rules that are in place.

 

 

Hopefully this won't ever happen in production (resources at both datacenters unavailable), but I'm just curious as to what I can expect in this situation?

 

 

 

Thanks,

 

 

 

Josh