Cyrus IMAP Readonly partitions

Ken Murchison murch at
Thu Mar 29 13:57:36 EST 2007

Michael D. Sofka wrote:
> I am working on a way to recover deleted (and purged) messages in Cyrus
> IMAP.  This is not as silly as it may at first sound.  On Exchange there
> is a setting whereby deleted items are not deleted from the server until
> they are backed up.  Before this time, they can be ``recovered'' from
> the deleted items folder.  (Why not, they're still available to the
> system.)
> Likewise, in our AFS file space (those were the days) we mount the
> read-only backup volume in a directory called "./yesterday" so that
> "oops, I didn't mean to delete that!" did not result in a phone call to
> operations to restore a file.  In AFS the backup volume is a "copy on
> write" snapshot of the volume created for backup.  Mounting these gave
> access to the contents prior to the start of that day's backup.  (And,
> AFS and Cyrus IMAP share a mother, if only by adoption.... :-)
> With that as background, our Cyrus IMAP servers use LVM snapshots for
> backups.  We make the snapshot, mount it, back it up, and unmount it.
> Fairly standard.  After a couple calls to restore "oops" inboxes, I
> thought maybe the snapshot could be mounted as a read-only IMAP
> partition.  Users could access this to recover accidentally deleted
> messages.
> Alas, it is not quite that simple.  The snapshot would just appear
> to Cyrus IMAP.  The mailboxes database would then have to be updated
> with this new information, the access information would need to be
> set, etc.  However, I am wondering if there isn't some trick,
> latent, in Cyrus IMAP to allow this feature. (If not, it goes on
> my way to long projects list---and I wouldn't mind if somebody
> beat me to it.)


This might be worth discussing on the cyrus-devel at list.

Kenneth Murchison
Systems Programmer
Project Cyrus Developer/Maintainer
Carnegie Mellon University

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