[Dovecot] SIS and restoring from backups

[Timo Sirainen]

On 24.3.2012, at 14.01, Charles Marcus wrote:

> On the question of the existing SIS capability for attachments... have you given any thought as to how to solve the problem of restoring from backups when SIS is used? I was planning on using it initially, until I read on list that restoring from (normal disk-to-disk) backups would not work when SIS was enabled - this is obviously a deal breaker for anyone who relies on backups - which I would think would be almost everyone?
> 
> Or maybe I misunderstood the problem?

You can do full backups from a filesystem snapshot, which works "well enough" (might leave some unused attachments lying around in some rare cases, but that can also happen if Dovecot crashes/dies).

The other possibility is to already use dsync (doveadm backup) to do full backups. With the redesigned dsync you would be able to do incremental backups also. In any case the solution involves de-SISing mails for backup.