Background: We are using Smartermail Enterprise Edition as our primary mail server, with two Smartermail Free Edition Incoming/Outgoing Gateways. Although we have two fail-over connections (one Fiber, one T3) at our primary Data Center, we are in an isolated area that is prone to service-disruptions as they share the same geographical upstream link/route that is maintained by a Tier 2 firm (who controls all traffic in/out of our geographical area) that is unable to properly grep BGP and thereby causing short (@ 2 hour) outages at least once a week. We are wanting to add additional fail-over for mail services by moving some systems to our secondary Data Center which has more reliable upstream routes from Tier 1 providers.
Question: If we move one of our DNS Servers, and one of our Incoming/Outgoing Gateways to our second Datacenter, would we also be able to use Smartermail Enterprise Edition clustering to work across multi-site clustering? I know that Microsoft Windows Server 2012 supports this type of clustering but was unsure if Smartermail Enterprise Edition supported multi-site clustering.
If Smartermail Enterprise Edition does support multi-site clustering, how would one configure DNS for customer POP/IMAP/SMTP to find the off-site location in the event of not being able to connect to our primary Data Center? (Would round-robin DNS work or would this break email services?)