[Dovecot] Mail replication ... totally confused !

[HL]

Hello,

I am totally confused configuring replication in dovecot.

In my case I have 2 servers
instead of running rsync as a daemon which takes a lot of time
I would like



SERVER-A will be the master
and
SERVER-B will be the slave

My users directly interact with server A,
Server B stands as a mails backup only

I've setup SERVER-B ( backup ) like that, NO SPECIAL CONF on master 
SERVER-A

Is this ok ??
I Don't want to miss any mails
Since this is a live server

    service aggregator {
         # give enough permissions for mail processes
         #
         fifo_listener replication-notify-fifo {
                 user = vmail
                 mode = 0600
         }
         unix_listener replication-notify {
                 user = vmail
                 mode = 0600
         }
    }
    service replicator {
         # start replication at startup
         #
         process_min_avail = 1
    }
    service doveadm {
         # if you're using a single virtual user, set this to start ssh 
as vmail
         # (not root)
         #
         user = vmail
   }
    service config {
         # needed to grant access to /var/run/dovecot/config for service 
doveadm
         #
         unix_listener config {
                 user = vmail
         }
    }

  dsync_remote_cmd = ssh -p 1234 -l%{login} %{host} doveadm dsync-server 
-u%u -l%{lock_timeout} -n%{namespace}

plugin {
         mail_replica = remote:vmail at master-server-a.tld
         replication_full_sync_interval = 1 hours
    }