Agree, but five nines are not 100% ;) Anyway - this discussion reminds me of Technical Report 85.7 - Jim Gray, which might be of the interest to some of you.

a lot of things are possible if you are lucky enough ;)

well this is probably PR as there is no such system nor it can be made that can have 100% uptime. not talking about the fact that network engineers rarely work with servers :)

One way to do it is with ImapSync: https://imapsync.lamiral.info