Quoting Alexander Chekalin achekalin@lazurit.com:
With Maildir the message GUID is typically the same as the
Maildir base filename (i.e. everything before ':' character).But what if I one day decide to convert my maildir's to mbox'es? I really plan to do such conversion in a while (as soon as I finish the indexing system).
mbox? or mdbox? With mbox there are no proper GUIDs, but Dovecot kind of fakes it by returning MD5 of specific headers as GUIDs (so not 100% reliable). With mdbox GUIDs work even better than with Maildir, the GUID is always stored in the message's metadata.
I'd like to use the best optimized one (mdbox), but there is a
reason not to do that is when I use mbox or maildir I can see where
given IMAP folder mails are stored, so, say, if I want to copy only
one IMAP folder to some remote site, I just copy know dir or file.
With mdbox this is different, I simply can not guess where my
messages exactly are.If it be possible to have per-IMAP-folders mdboxes, I love to use
it. But from what I know and tried this is not way mdbox used to
work, right?
You can always use the info from the wiki, I took some code from it to
create this little script, that dumps my spam folder and uses it to
learn. Basically dumps a mailfolder back into maildir format.
doveadm search -u $useraccount mailbox Spam | while read guid uid; do
doveadm fetch -u $useraccount text mailbox-guid $guid uid $uid >
msg.$uid; done
If your using mdbox on the other end, you could reimport them I
suppose, I haven't looked into doing that, since I haven't needed that
yet.