[Dovecot] Maildir configuration vs ZFS and snapshots...

[Peter Eriksson]

I have a little tricky issue around here. First some background:

Every user is assigned their own ZFS filesystem, and it's mounted as
/home/USER with a Maildir inside it. The there is a filesystem snapshot
(read-only) taken automatically every day by the system. The idea is
to allow users easy access to backup copies of their mail so that they 
can restore things themself..

For example this structure (somewhat abbreviated, some files/dirs removed):

/home/testson/
	.zfs/
		snapshot/
			2007-06-18/
				Maildir/
					cur/
					new/
					tmp/
					.Trash/
						cur/
						new/
						tmp/
	Maildir/
		cur/
		new/
		tmp/
		.Trash/
			cur/
			new/
			tmp/


Now,I can access the normal Maildir INBOX and folders nicely via
Dovecot/IMAP. The thing is I'd like to be able to access the
snapshot too via Dovecot/IMAP somehow. My first idea was to use
Dovecots namespace feature like this in the config file:

	namespace private {
	  separator = /
		  prefix = snapshot/
		  location = 
maildir:~/.zfs/snapshot/2007-06-18/Maildir:CONTROL=~/.dovecot/control:INDEX=~/.dovecot/index
	}

This works great for the mail folders inside the Maildir - but not for 
the INBOX which isn't displayed at all... (Ie, under the "snapshot" 
prefix I only see "Trash" etc when looking at the folder from an IMAP 
client).

I think that I'd need to use the "INBOX=" option for Dovecot to see the 
top-level "new/cur/tmp" directories in the snapshot folder, but you can 
only have one INBOX if I'm not mistaken?

Any suggestions on how best to configure this?

- Peter