external storage for mail attachments

[Oscar del Rio]

On 02/ 3/16 03:47 PM, zucca at systemschmiede.com wrote:
>
> was wondering if it was possible to store mail attachments on a separate 
> storage with dovecot, and if so, how.
> Of course a single instance storage of these attachments would also be a 
> very good thing, allthough not a basic prerequisite.
>

Yes.  The description of the settings are in conf.d/10-mail.conf

##
## Mail attachments
##

# sdbox and mdbox support saving mail attachments to external files, which
# also allows single instance storage for them. Other backends don't support
# this for now.

# Directory root where to store mail attachments. Disabled, if empty.
#mail_attachment_dir =

# Attachments smaller than this aren't saved externally. It's also possible to
# write a plugin to disable saving specific attachments externally.
#mail_attachment_min_size = 128k

# Filesystem backend to use for saving attachments:
# posix : No SiS done by Dovecot (but this might help FS's own deduplication)
# sis posix : SiS with immediate byte-by-byte comparison during saving
# sis-queue posix : SiS with delayed comparison and deduplication
#mail_attachment_fs = sis posix

# Hash format to use in attachment filenames. You can add any text and
# variables: %{md4}, %{md5}, %{sha1}, %{sha256}, %{sha512}, %{size}.
# Variables can be truncated, e.g. %{sha256:80} returns only first 80 bits
#mail_attachment_hash = %{sha1}