I have a customer with 2 locations and am considering putting a deb12 server at each (one now has a deb12 server) . the issue is connectivity at one of the locations may go down from time to time. they dont want to lose emails etc (yes I explained to them you dont really lose emails unless down for >10 days) Can I setup the 2 servers to mirror sites and emails (/var/www and /var/mail) between them (GlusterFS?) so that if one is ns1 and the other ns2 they could retrieve mail from either one that is up? files as well? there would have to be MX entries for both so that emails arriving on either would be visible to both and if one was down the email would be delivered (asap?) to the one that was up? Is this feasible? worthwhile? or is Till just scratching his head saying WTF?
What you can do for email is the following setup: -> ISPConfig Mirror Mailserver -> Dovecot Replicator between the two servers -> Cloudflare(or any other service that does this) load balancer that checks downtime and changes DNS Records when the main location goes down This is an overkill setup for a single customer and brings lots of work with it.
