Server migration

[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

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.

> 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?

> If you don't want or cannot set up replication you could still do a one-shot
> migration via Dovecot's dsync[2] on the new server, pulling the mails from
> the old. 50GB isn't that much as long as your two servers are at least
> connected with 100 Mbit to the inet. You may want to block for the time of
> the migration via iptables your users accessing Dovecot. However, under the
> bottom-line, if this is really necessary depends on you and the needs of
> your mailusers/customers.

I can't block the whole server. I have to migrate 1 user at once.
But I can disable the pop3/imap access for that user, so noone is
changing the files during the migration
(except for the postfix/exim delivery agent)

> P.S. You should think about to use on the new server mdbox as mailbox
> format.
> That's kinda a hybrid of mbox and maildir and benefits of features of both
> its predecessors. However, backup and restoring is in case of mdbox "a bit"
> different. Just have a read...
>
>
> [1] http://wiki.dovecot.org/Replication
> [2] http://wiki2.dovecot.org/Migration/Dsync

Thank you