Andreas,
I am interested in finding out your experiences with using the dbox format (especially mdbox) if you use this format.
mdbox is THE reason why I am trying Dovecot. With mailboxes of several (tens of) GB with several k of messages I hope mdbox will speedup backups. Also SIS for attachments sounds very good, but still doesn't follow the altstorage rules (while messages go to altstorage, the extracted attachment stays in the SIS partition).
I am contemplating changing my maildir setup to mdbox but I still need to make a case for it
My current interest is to keep live mailbox data in Maildir format and "archive" in the altstorage in mdbox after 30 days or so. I will experiment that configuration next week.
Nevertheless I am still puzzled by the lost data I got yesterday in my mdbox+SIS+altstorage combination (see my message and the one from Daniel Miller).
I am also interested to hear real life stories.
73 Paolo Cravero