[Dovecot] Compressed mail archives

[Timo Sirainen]

On 12.5.2010, at 14.44, Will Palmer wrote:

> Googling around, I've seen a lot of messages related to compressing
> individual messages in a maildir. However, what I'm really looking for
> is a solution which will allow multiple messages to be compressed into a
> single compressed file, while still allowing those messages to be
> accessed via IMAP.

mbox is the only possibility for that. mdbox supports compression, but only one message at a time.

> But really I don't even know if it's possible
> to have dovecot support MBox and Maildir simultaneously, nor do I know
> enough about the MBox format to even know if the IMAP-style "multiple
> mailboxes" thing is possible in MBox.

It is. Just create two namespaces, one for maildir (prefix="") and one for mbox (prefix=archive/). See examples in http://wiki.dovecot.org/Namespaces

> And of course, any way you slice it, 20,000 mails,
> compressed or not, sent to five people, take up 100,000 mails worth of
> space if you don't share them between accounts. (perhaps they could even
> simply be hard-linked to the same file?)

http://wiki.dovecot.org/LDA : -p <path>: Path to the mail to be delivered instead of reading from stdin. If using maildir the file is hard linked to the destination if possible. This allows a single mail to be delivered to multiple users using hard links, but currently it also prevents deliver from updating cache file so it shouldn't be used unless really necessary. (v1.1+)