I'm going to deploy postfix + dovecot + CephFS( as Mail Storage). Basically I want to use two servers for them, which  is kind of HA.

 

    My idea is that using keepalived or Pacemaker to host a VIP, which could fail over the other server once one is down. And I'll use Haproxy or Nginx to schedule connections to one of those server based on source IP( Session stickiness),  I'll use VIP as DNS record.etc, is my plan doable?

   I know MX could be server ones with different priority. But I think it brings along shortage that DNS couldn't know Email server is up or down, it just returns results to MUA, right?

   Thanks for any suggestions and ideas. 

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