dovecot - Sep 2014 - Migrating from 2.0.x to 2.2

Hi

I'm about to migrate a setup with <20 IMAP (but with a few million mails
in all) accounts that belong to the same system-user on an older machine running
Dovecot 2.0.13 to a new machine running Dovecot 2.2.13 (or possibly newer..).

Mails are stored in Maildirs with no special or advanced features (like
alternate storage etc etc).
Filesystems are prepared for the expected amount of inodes required, and for the
time beeing a change to mdbox is seen as an added complexity.

One requirement of the migration is that messageID is not changed - mails are
referenced by other systems that expect to find individual mails by the ID.

Since dsync is incompatible between 2.0<->2.1<->2.2 what is the best
way to perform this migration?

I was hoping of rsync'ing all Maildirs from the old machine to the new one
(including indexes etc etc) and power up Dovecot 2.2.x and see what happens, but
is that possible or is there another (and better) way short of installing 2.0.x
on the new machine, rsync everything and then upgrade to 2.2.x?

Regards,
Jens Dueholm Christensen

Am 05.09.2014 um 11:54 schrieb Jens Dueholm Christensen:
> Since dsync is incompatible between 2.0<->2.1<->2.2 what is the
best way to perform this migration?
> 
> I was hoping of rsync'ing all Maildirs from the old machine to the new
one (including indexes etc etc) and power up Dovecot 2.2.x and see what happens,
but is that possible or is there another (and better) way short of installing
2.0.x on the new machine, rsync everything and then upgrade to 2.2.x?
use rsync!

especially because it is fast after the first "hot sync"
and you can repeat the sync, look if all is fine and
after you are sure config and data are OK

* stop services on both machines
* rsync a last time
* start services on the new machine
* change IP or DNS

well, and since you don't change data on the old one you
have a untouched backup there




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On 2014-09-05 11:54, Jens Dueholm Christensen wrote:
> Filesystems are prepared for the expected amount of inodes required,
> and for the time beeing a change to mdbox is seen as an added
> complexity.
With that amount of mails in mind, a migration to mdbox is a good idea, 
IMHO.
> One requirement of the migration is that messageID is not changed -
> mails are referenced by other systems that expect to find individual
> mails by the ID.
> 
> Since dsync is incompatible between 2.0<->2.1<->2.2 what is the
best
> way to perform this migration?
IIRC dsync can be run independently from a running dovecot server. If 
that is correct, then you could install dovecot 2.2 at the old server, 
and use that dsync 2.2 for migration to the new server by simultaneously 
changing the mail storage format. Again, IIRC, all your message IDs 
shouldn't be modified during that approach.

Just give it a try ;-)

Regards,
Michael