dovecot - Jul 2007 - Maildir configuration vs ZFS and snapshots...

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

On Tue, 2007-07-03 at 16:20 +0200, Peter Eriksson wrote:
> 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).
Try "ln -s . .INBOX". I'll probably fix this for v1.1, but I
already
tried once for v1.0 and it got too messy.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: This is a digitally signed message part
URL:
<http://dovecot.org/pipermail/dovecot/attachments/20070703/ede1ac9e/attachment-0002.bin>

Timo Sirainen wrote:
> On Tue, 2007-07-03 at 16:20 +0200, Peter Eriksson wrote:
>> 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).
> 
> Try "ln -s . .INBOX". I'll probably fix this for v1.1, but I
already
> tried once for v1.0 and it got too messy.
It won't confuse Dovecot (and/or external mail programs accessing the 
Maildir directly like procmail and/or a directly accessing Pine for 
example)?

<resignated *sigh*>
Oh how easy this had been if the Maildir standard had been sane and used
real directories without dots, in a tree structure for the folder 
structure (and used .new/, .cur/ and .tmp/ for the folder data) - then
I could have just put a pointer to "~/.zfs/snapshot" and have had
*all*
the snapshots show up under the "snapshot/" namespace more or less 
automatically :-).
</>

- Peter

Greetings -

I'm intrigued by your suggestion of providing read-only access to  
mail folders in the snapshots...

On 3 Jul 2007, at 15:20, Peter Eriksson wrote:
> 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).
We are switching from the UW IMAP server with local disks to Dovecot  
using a NetApp filer.  The filer provides snapshots too, although  
with a slightly different layout as the ".snapshot" directory appears
in each and every directory with its files and folders.  For example:

     ~/Maildir/.snapshot/nightly.0/...
     ~/Maildir/.snapshot/nightly.1/...
     ~/Maildir/.snapshot/nightly.2/...
         etc

where the ".0" suffixed directory is the most recent etc.

In your example your snapshots seem to be in directories named after  
a specific date (when the snapshot was taken?).  I was wondering if  
you had some clever way of providing access to these; in your example  
above you hard-code the names into the Dovecot configuration file,  
which doesn't seem practical for a live system?

Basically I'm trying to mimic your setup and was wondering if you had  
already solved the problem of getting down from your "snapshot"  
directory through the intermediate level to the Maildir itself.

In passing, would I need to use a separate CONTROL and INDEX storage  
area for these, or will the files for the snapshot folders live  
happily alongside those for the live area?  (I'm not too sure how the  
organisation of these storage areas works when namespaces and  
prefixes are concerned!)

Cheers,
Mike B-)

-- 
The Computing Service, University of York, Heslington, York Yo10 5DD, UK
Tel:+44-1904-433811  FAX:+44-1904-433740

* Unsolicited commercial e-mail is NOT welcome at this e-mail address. *