[Dovecot] dsync replication errors

[Timo Sirainen]

On 17.2.2013, at 12.19, Michael Grimm <trashcan at odo.in-berlin.de> wrote:

> On 17.02.2013, at 11:08, Timo Sirainen <tss at iki.fi> wrote:
>> 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. :)
> 
> Ok, that won't hit me for the time being because I am using mdbox.

It's basically the same with mdbox, except instead of using actual hostname it's using a 32bit hash of it. (So yeah, ideally there should be checks for detecting hostname hash collisions..)