dovecot - Aug 2010 - Cyrus to Dovecot migration (OS X Server): Backup + restore messages, live "standby server" and delayed expunge and…

Hi List,

I am very close to migrating from Cyrus to Dovecot (to be more precise
from Mac OS X Server 10.5.8 to 10.6.4).
The latter is reporting the dovecotd version to be 1.1.20apple0.5.
All I have read about dovecot is extremely positive so I am exited to
make the switch.


BACKUP:
BUT I would like to be sure that I can make a sound backup strategy.
For Cyrus i used topicdesk's mailbfr (a script that stops the
mailservice and then rsync's the mailstore to a backup location
incrementing daily and restarting a complete backup weekly).

This script is not yet ready for Dovecot, but from what I have read it
should be as easy as "just" backing up the mail-data
(/var/spool/imap/dovecot/mail in OS X), eg. with rsync.

Our current setup is requiring ca. 11 hours for a full (200+ GB)
backup (weekly) this is not good for uptime?


RESTORE:
Restore should be the same (well reverse) "just" restoring the files
and making sure the get the correct permissions.
What I am not sure about is the (cyrus specific) need for
reconstructing the database, as I have read (on this list) it seems
that dovecot is designed better and will "automatically" recognised
the restored messages without the need to reconstruct any databases or
stopping+restarting the service.
Is this really true ,-)?
NB.: For restores I plan to always restore to a specific subfolder for
the user (eg RESTORED MAIL) as opposed to placing the mails within the
folder hierachy



LIVE BACKUP SERVER
I have been told, that dovecot provides clever mechanisms for making
it possible to synchronise the data to a "hot-spare" server. Both for
being able to provide access to the data during breakdown or planned
maintenance, but perhaps also to make backups easier (perhaps not
needed?)



DELAYED DELETION OF MESSAGES
I believe that the feature is called "delayed expunge", a way of not
deleting the messages until after an additional delay from the time
the user deletes the message. Is this possible in dovecot?



DOCUMENTATION
Where would the best FAQ/KB for getting to know dovecot better be,
perhaps there have even been written good books (I know old fashioned,
but I really like the physical hands on a real book provides ;-)

It's a lot of questions and I hope for good pointers to where I can
find more documentation and good feedback from the list.


BR Thomas von Eyben

On 05/08/2010 10:28, Thomas von Eyben wrote:
> Hi List,
>
> I am very close to migrating from Cyrus to Dovecot (to be more precise
> from Mac OS X Server 10.5.8 to 10.6.4).
Just a tip, but during my migration I first switched all users to point 
at dovecot, but used the "proxy" feature to point them back to the 
original mail server.  This allowed me to migrate across just one user 
at a time and check for problems until I have all users migrated onto 
Dovecot.

This doesn't help you with the other stuff, but it may give you a soft 
way to migrate a bit more slowly than a big bang?

Good luck

Ed W

On Thu, 2010-08-05 at 11:28 +0200, Thomas von Eyben wrote:
> RESTORE:
> dovecot is designed better and will "automatically" recognised
> the restored messages without the need to reconstruct any databases or
> stopping+restarting the service.
> Is this really true ,-)?
Yes.
> DELAYED DELETION OF MESSAGES
> I believe that the feature is called "delayed expunge", a way of
not
> deleting the messages until after an additional delay from the time
> the user deletes the message. Is this possible in dovecot?
There's a lazy_expunge plugin:
http://wiki.dovecot.org/Plugins/Lazyexpunge
> DOCUMENTATION
> Where would the best FAQ/KB for getting to know dovecot better be,
> perhaps there have even been written good books (I know old fashioned,
> but I really like the physical hands on a real book provides ;-)
There's the wiki of course, but other than that I don't know really.
I'm
not aware of any Dovecot books (although one is being started I think).