Server migration

[Michael Seevogel]

Am 24.10.2016 um 15:25 schrieb Gandalf Corvotempesta:
> 2016-10-24 14:47 GMT+02:00 Michael Seevogel <ms at ddnetservice.de>:
>> If your server OS supports newer Dovecot versions then I would highly
>> suggest you to upgrade to Dovecot 2.2.xx (or at least to the latest 2.1) and
>> set up Dovecot's replication[1] feature.
>
> Are you talking about the new server or the older one that I have to replace?
> The new server has to be installed from scratch, so, yes, I can use Dovecot 2.2
> from Jessie

I meant your old server. With "old" I was expecting something like 
Debian Sarge or SuSE Linux 9.3. That would have been really old, but 
since you are on Debian Squeeze, I would definitely choose the way with 
an upgraded Dovecot version and its replication service.

>
> The "old" server is based on Squeeze, I can upgrade that to Wheezy and install
> Dovecot 2.2 from wheezy-backports but I have huge trouble when I've tried to
> do the same on a similiar server. I was unable to upgrade the dovecot
> configuration
> by following the documentation as this didn't work:
>
> doveconf -n -c /etc/dovecot/dovecot.conf > dovecot-2.conf
>
> I had an empty  dovecot-2.conf file, no warning or output at all. It
> did nothing.
>

Well, I'am not too familiar with Debian since I'am a Red Hatter but 
perhaps you could use the binaries from there: 
http://wiki2.dovecot.org/PrebuiltBinaries

Dunno if you have to rebuild the binaries, or if you can install them 
straight on Squeeze. You could also try to convert your old dovecot.conf 
on a different machine (maybe your new server?) and then just copy it 
back to your old server.

As a last straw you could certainly adapt the dovecot.conf for Dovecot 
2.2 manually, it shouldn't be too complicated, but this is totally up to 
you.


>> With this method you can actually archieve a smooth migration while your
>> current server replicates all emails in real time to your new server,
>> including new incoming emails and also mailbox changes to your new server
>> and when the migration is done you'll just have to change your DNS and
>> disable the Replication service.
>
> Cool.
> Any guide about this ?
> Should I start the replication on one side and wait for finish before
> pointing the mailbox to the new server?


How to setup and start replication is described here: 
http://wiki2.dovecot.org/Replication

Also make sure that you migrate/copy your userdb from the old server to 
the new server and that you properly test the user-mailbox access on the 
new server before you start the replication process.

Regarding replication:
I would wait with adjusting the DNS records until the replication has 
finished and you know that the new server works as expected.

However, you may want to keep the replication process running for one or 
two more days to catch emails still arriving due to DNS caching times on 
your old server. The same may apply to mailusers that still access your 
old server via POP3/IMAP.



Best regards
Michael Seevogel