Retrieving mail from read-only mdbox

[Teemu Huovila]

On 01.06.2017 00:30, Mark Moseley wrote:
> This is a 'has anyone run into this and solved it' post. And yes, I've been
> reading and re-reading TFM but without luck. The background is that I'm
> working on tooling before we start a mass maildir->mdbox conversion. One of
> those tools is recovering mail from backups (easy as pie with maildir).
> 
> We've got all of our email on Netapp file servers. They have nice
> snapshotting but the snapshots are, of course, readonly.
> 
> My question: is there a doveadm command that will allow for email to be
> retrieved from a readonly mdbox, either directly (like manipulating the
> mdbox files directly) or by doveadm talking to the dovecot processes?
What would this tooling do exactly? Is it for restoring the users existing (writable) account from a read-only backup? I would in that case recommend looking into using "doveadm backup" or "doveadm sync". They do provide som crude selection of messages on e.g. folder level.

In case you you are aiming to provide users online access to their own backups, maybe add them as a read-only mailbox using ACLs. Though other mails in this thread indicate there still might be problems.

br,
Teemu

> 
> Ideally, there'd be something like doveadm dump, but that could dump
> selected message contents.
> 
> I've tried using IMAP with mail_location pointed at the snapshot, but,
> though I can get a listing of emails in the mailbox, the fetch fails when
> dovecot can't write-lock dovecot.index.log.
> 
> If anyone has gotten something similar to work, I'd love to hear about it.
> A working IMAP setup would be the ideal, since it's more easily automatible
> (but I'll take whatever I can get).
> 
> Any and all hints are most welcome!
>