dbox configuration
==================

See <MailboxFormat.dbox.txt> for a description of the dbox mailbox format.
NOTE:*You must not lose the dbox index files, they can't be regenerated without
data loss*.

Mail location
-------------

dbox can be used in two ways:

 1. One message per file (*single-dbox*), similar to <Maildir>
    [MailboxFormat.Maildir.txt].
 2. Multiple messages per file (*multi-dbox*), but unlike <mbox>
    [MailboxFormat.mbox.txt] multiple files per mailbox.

To use *single-dbox*, use the tag 'sdbox' in the <mail location>
[MailLocation.txt], for example:

---%<-------------------------------------------------------------------------
# single-dbox
mail_location = sdbox:~/dbox
---%<-------------------------------------------------------------------------

For backwards compatibility, 'dbox' is an alias to 'sdbox' in the mail
location.

To use *multi-dbox*, use the tag 'mdbox' in the <mail location>
[MailLocation.txt], for example:

---%<-------------------------------------------------------------------------
# multi-dbox
mail_location = mdbox:~/mdbox
---%<-------------------------------------------------------------------------

Alternate storage
-----------------

dbox has a feature for transparently moving message data to an <Alternate
storage> [MailboxFormat.dbox.txt] area.

To specify an alternate storage area, use the 'ALT' parameter in the mail
location. For example, specifying the mail location as:

---%<-------------------------------------------------------------------------
mail_location = mdbox:/var/vmail/%d/%n:ALT=/altstorage/vmail/%d/%n
---%<-------------------------------------------------------------------------

will make Dovecot look for message data first under '/var/vmail/%d/%n', and if
it is not found there it will look under '/altstorage/vmail/%d/%n' instead.

Keep the unmounted '/altstorage' directory permissions such that Dovecot mail
processes can't create directories under it (e.g. root:root 0755). This way if
the alt storage isn't mounted for some reason, Dovecot won't think that all the
messages in alt storage were deleted and lose their flags.

Mailbox directory name
----------------------

When using the default hierarchical layout, there is a potential for naming
collisions between dbox's 'dbox-Mails/' subdirectory and mail folders of the
same name. For example, consider a mail folder "foo/bar". Under the default
hierarchical layout, data about this mail folder would be stored at
'~/mdbox/mailboxes/foo/bar/dbox-Mails/'.

If the user then tried to create a mail folder "foo/bar/dbox-Mails", this would
then imply that data would be stored at
'~/mdbox/mailboxes/foo/bar/dbox-Mails/dbox-Mails/'. But this would overlap the
'dbox-Mails/' subdirectory of mail folder "foo/bar".

This may not be a problem in many installations, but if a risk of collisions
with the default name "dbox-Mails" is perceived, then the 'DIRNAME' parameter
can be used. For example, if we specify mail location as:

---%<-------------------------------------------------------------------------
mail_location = mdbox:~/mdbox:DIRNAME=DbOx-mAiLs
---%<-------------------------------------------------------------------------

then this will make data for mail folders be stored in a subdirectory
'DbOx-mAiLs/' instead of the default 'dbox-Mails/', so a mail folder "foo/bar"
would have data stored at '~/mdbox/mailboxes/foo/bar/DbOx-mAiLs/'.

The value for 'DIRNAME' should be chosen carefully so as to minimise the
chances of clashing with mail folder names. In the example here, unusual
upper/lower casing has been used.

(This file was created from the wiki on 2019-03-05 04:42)