See dbox for a technical description of Dovecot’s dbox mailbox format.
NOTE: You must not lose the dbox index files, as they can’t be regenerated without data loss.
To use single-dbox, use the tag
sdbox in the
# single-dbox mail_location = sdbox:~/dbox
For backwards compatibility,
dbox is an alias to
sdbox in the mail
location. (This usage is deprecated.)
To use multi-dbox, use the tag
mdbox in the
# multi-dbox mail_location = mdbox:~/mdbox
See dbox alternate storage for further information.
To specify an alternate storage area, use the
ALT parameter in the mail
location. For example:
mail_location = mdbox:/var/vmail/%d/%n:ALT=/altstorage/vmail/%d/%n
will make Dovecot look for message data first under
(“primary storage”), and if it is not found there it will look under
/altstorage/vmail/%d/%n (“alternate storage”) instead. There’s no problem
having the same (identical) file in both storages.
Keep the unmounted
/altstorage directory permissions such that Dovecot
mail processes can’t create directories under it (e.g.
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.
mdbox Configuration Settings¶
mdbox only: If enabled, preallocate space for newly created files.
In creation of new mdbox files, their size is immediately preallocated as mdbox_rotate_size.
This setting currently works only in Linux with certain filesystems (ext4 and xfs).
mdbox only: The maximum age the dbox file may reach before it’s rotated.
0 means there is no age-based rotation.
mdbox only: The maximum size the dbox file may reach before it is rotated.