Problems setting up SIS (duplicate files with same hash)

[Joe Beaubien]

I'm starting to think there is something I don't understand about running
dovecot with SIS.

After I deleted the 3 emails that have the same attachment, the 3
attachments are still on disk (saved under the name of the hash).

After running doveadm purge & doveadm deduplicate, the 3 attachments are
still on disk (the 3 emails were the only emails on server, so I can
guarantee that no other emails are pointing to the attachments).

*What am I not understanding?* It makes no sense that the attachments would
never be cleaned, so I am sure I am missing something.

Best regards,

Joe B

On Sat, Sep 5, 2015 at 11:40 AM, Joe Beaubien <joe.beaubien at gmail.com>
wrote:

> Hi everyone,
>
> I am currently trying to setup our next dovecot server (2.2.18) with SIS
> enabled, but I have enconutered 1 problem and 1 question:
>
>
> *1) Same attachment, different filenames*
>
> I have a feeling a misconfigured something (or forgot to do something)
> because SIS almost works, but not quite since 3 identical attachment take
> 3x the space (see end of email for my SIS config).
>
> For 3 the emails I sent with the same attachment, I got 3 seperate files
> with the same hash name but a different string following the dash:
>
> -rw------- 1 info info 2.6M Sep  5 11:14
> e35083e3280a21c6aaabbae8cb23d54493f514a5-6a22711a7b05eb5509480000045c9bf4
> -rw------- 1 info info 2.6M Sep  5 11:16
> e35083e3280a21c6aaabbae8cb23d54493f514a5-6c22711a7b05eb5509480000045c9bf4
> -rw------- 2 info info 2.6M Sep  5 11:18
> e35083e3280a21c6aaabbae8cb23d54493f514a5-6e22711a7b05eb5509480000045c9bf4
> drwx------ 2 info info 4.0K Sep  5 11:18 hashes
>
> For the record, the "hashes" subfolder has only 1 hash
> (e35083e3280a21c6aaabbae8cb23d54493f514a5) which perfectly matches the
> first part of the 3 filenames.
>
>
>
> *2) Saving attachments under a generic name or more flexible permissions?*
>
> It seems that dovecot saves the attachment with the username and group of
> the user who has received the email.
>
> Is it possible to have dovecot save the attachments as a generic user
> (like dovecot or dovenull) so that all my different users can share the
> same pool of attachments?
>
> Alternatively, is it possible to have dovecot save the attachment under
> more flexible permissions so that they can be shared between users?
>
> This would allow us to save alot of disk space.
>
>
> *Here is the SIS config I am using:*
>
> mail_attachment_dir = /data/emails/attachments
> #mail_attachment_min_size = 128k
> #mail_attachment_fs = sis posix
> #mail_attachment_hash = %{sha1}
>
>
>
> Any help would be very much appreciated.
>
> Thank you,
>
> Joe B
>