Doveadm backup...

[John Stoffel]

>>>>> "Sami" == Sami Ketola <sami at ketola.io> writes:

>> On 27. Mar 2022, at 23.09, John Stoffel <john at stoffel.org> wrote:
>> 
>>>>>>> "Stephane" == Stephane Magnier <steph.mag220 at netcourrier.com> writes:
>> 
>> Sorry, I deleted your most recent email post before I could reply.
>> But why don't you just do 'imapsync' instead from your production
>> dovecot box to some other backup system?  Otherwise I'd probably work
>> to setup dovecot's own replication but only have it go one way.
>> 
>> For example, I've got a VPS out in the cloud for my email, and I
>> should probably back it up to my home system using replication, but it
>> would be strictly primary->secondary.  I wouldn't be trying to run two
>> primaries replicating between each other.
>> 
>> Imapsync would be an improvement over rsync because it works within
>> dovecot, so you'd get a more consistent view, but maybe not quite as
>> upto date.  But how important is your email if you worry about losing
>> 20 minutes worth of it?  If it's that critical, then you should be
>> investing in a more robust setup.

Sami> I would not recommend using imapsync to do backups as it loses
Sami> data.  There is no way for imapsync to retain all data as for
Sami> example IMAP protocol does not allow client to set email UID
Sami> numbers. Backup made with imapsync is always partial copy of the
Sami> original and cannotbe restored identically.

That's true, it's a bit brute force and not ideal.  But if you can't
setup properly doveadm replication, I would think that imapsync is
better than rsync, unless you can pause dovecot/postfix, snapshot the
filesystem, unpause dovecot/postfix then rsync the snapshot to your
remote backup server.

But I also think that if you're that terrified about losing email,
getting dovecot's replication working even just one way would be an
improvement.


But the OP doesn't really state his requirements for getting back
online.  If it's a personal site (like mine) then I can take my time,
it's not *that* critical.  If it's a customer setup, then why aren't
you running replication already, with dovecot director and shared
resilient storage behind it?