> If your server is down, mail delivery is tried every couple of hours for
> days. So - if your server is down for a day or two, no email should get
> lost.

Fortunately the server went down very few times, but the last one lasted almost two days
and I lost a lot of mail on multiple mailboxes.
Even though I work alone, it is still a business server and I can't afford these things.

> then configure a second MX with
> the same SMTP and dovecot configuration, then configure replication
> between the two dovecot instances. https://wiki.dovecot.org/Replication

I had read this page on replication, but I didn't understand how I can access the second server.
Roundcube/Thunderbird are configured to access an IMAP / SMTP server that matches
their respective IP addresses, but here the IPs would become 2x2 = 4

>HTTP is another topic. If you also need high availibilty of your
> roundcube frontend, then you'd need a reverse proxy/load balancer in
> front of your server that can detect the outage and then direct the user
> to the other frontend on the second MX.

I already have Nginx as Reverse Proxy for Apache on my server.
However, if I understand your suggestion, I should install a third server for this purpose only.
Isn't there a guide to refer to?
I wouldn't even know what to look for on Google?

> PS: The text part in you email is broken (no line breaks).
I do not understand.
I am writing from the yahoo webmail.


Many thanks
A.