[Dovecot] dsync replication errors

[Timo Sirainen]

On Sun, 2013-02-17 at 10:44 +0100, Michael Grimm wrote:

> > Although even if it does, other parts of Dovecot still use only the hostname part to guarantee global uniqueness of things. So better to have unique hostnames.
> 
> What parts of Dovecot would be involved? I'm curious because my production mailservers use identical hostnames in their jails ever since running Dovecot (starting 1.x).

Mainly that maildir filenames are used as GUIDs. If two have the same
name, they are assumed to be identical. That's why the maildir filenames
include the hostname in them, to make sure that the GUID is different
even if two mails happen to be delivered at exactly the same time with
the same PID and same size to two different servers. So pretty unlikely,
but better to be safe. :)

There may be some other features that require unique hostnames in
future. Anything where multiple Dovecot servers need to communicate
between each others. If some day there is such generic communication
between Dovecot servers I'm planning on enforcing this requirement.