dovecot - Jun 2015 - SIS attachments compressed

Hello:

In case it is defined to use zlib compression, does SIS save attachments 
compressed?

I have found this question replied in the past (2012) and the answer was 
NO. I ask again just to know if there have been changes or if it is in 
the roadmap to add compression.

I have been testing to migrate from maildir+zlib to mdbox+zlib+sis and 
the results, in terms of space used, and worst than using just 
mdbox+zlib (without SIS), and suppose the reason in the lack of 
compression in attachments.

Thanks in advance.

-- 

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Juan Carlos Sanchez Hernandez
Responsable de  Seguridad y Correo Electronico
Servicio de Planificacion Informatica y Comunicaciones
Universidad Politecnica de Madrid
Rectorado
Avda. Ramiro de Maeztu 7
28040 Madrid
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> On 03 Jun 2015, at 18:29, Juan Carlos Sanchez <juancarlos.sanchez at
upm.es> wrote:
> 
> Hello:
> 
> In case it is defined to use zlib compression, does SIS save attachments
compressed?
> 
> I have found this question replied in the past (2012) and the answer was
NO. I ask again just to know if there have been changes or if it is in the
roadmap to add compression.
> 
> I have been testing to migrate from maildir+zlib to mdbox+zlib+sis and the
results, in terms of space used, and worst than using just mdbox+zlib (without
SIS), and suppose the reason in the lack of compression in attachments.
Pretty late reply, but nowadays there's fs-compress plugin. So something
like this should work (untested):

mail_attachment_fs = sis compress:gz:6:posix

It's a bit dangerous to enable this for existing attachments though, because
if there are any gziped attachments Dovecot will try to gunzip them before
sending to client, which causes problems. (So they should be double-gziped to
avoid this problem.)