[ubuntu-uk] How to back up Dovecot IMAP?

[Andrew Oakley]

I currently have all my email stored on a Dovecot IMAP server on my 
Ubuntu Dapper 6.06 server. I intend to upgrade this to Hardy using a 
total wipe, reformat and clean install (I have lots of crud on Dapper, 
such as Beryl, Automatix etc).

First I would like to back up everything on the IMAP server. How do I do 
this please?

Then, how do I restore this to a clean install of Dovecot?

Ideally I'd like to write a nice cron-able script that creates a .tar.gz 
file, but anything that works will do. For the longer term, how can I 
perform incremental Dovecot IMAP backups (say, only the last 7 days 
worth of mail)?

If it makes a difference, I am the only IMAP user on the server.

Couldn't find anything immediately relevant with Google, but links to 
RTFM-esque articles would much appreciated. Thanks,

-- 
Andrew Oakley