[Dovecot] rdiff-backup of Maildir?

[Thomas Harold]

What's the best way to do long-term backups of the Maildir format these 
days?  Traditionally we've just done a rdiff-backup or pointed Bacula at 
the Maildir.  Both give us the option to reset a particular mailbox back 
to a previous day (any day within the last N months).

Do we just need to snapshot the LVM volume that holds all the Maildir 
boxes, or is there some additional commands that we should run before 
doing the LVM snapshot?