

Mailbox Formats
===============


Mailbox formats supported by Dovecot: 

 * >>/mbox<<: Traditional UNIX mailbox format. Users' INBOX mboxes are commonly stored in '/var/spool/mail' or '/var/mail' directory. Single file contains multiple messages. 
 * >>/Maildir<<: One file contains one message. A reliable choice since files are never modified and all operations are atomic. The top-level 'Maildir' directory contains the 'Maildir/cur', 'Maildir/new' and 'Maildir/tmp' subdirectories. 
 * >>/dbox<<: Dovecot's own high performance mailbox format. Mails are stored in one or more files, each containing one or more messages. 
 * >>/Cydir<<: Dovecot's own simple and high performance Cyrus-like mailbox format. It should be mostly used for testing and benchmarking only. v1.1+ only. 
Mailbox formats *not* supported by Dovecot: 

 * >>/mbx<<: UW-IMAP's old high performance mailbox format. One file contains all the mailboxes, so expunges may still be slow. 
 * >>/mix<<: UW-IMAP's new (2006) high performance mailbox format. Similar to dbox. 
 * >>/mailstore<<: A format created by Exim. 
 * >>/MH<<: One file contains one message. Sort order of the folder determines the message ID and name.  Actively used by projects such as MH-E, NMH, exmh.  Experimentally supported by UW-IMAP [None]. 
 * >>/MMDF<<: Similar to mbox, but instead of From-line separators it uses four '^A' characters 
 * >>/Cyrus<<: One file contains one message, plus there are a couple of index/cache files. Commonly referred to as being maildir-like, although they have only a single thing in common. 
Adding support for new formats for Dovecot isn't very difficult, although it can be time consuming. Dovecot exposes a nice and simple API which needs to be implemented. 


Software Support
================


 *Format/Software* 
 *Dovecot [None]* 
 *UW-IMAP [None]* 
 *Courier-IMAP [None]* 
 *Exim [None]* 
 *Postfix [None]* 
 *PINE [None]* 
 *mutt [None]* 
 *procmail [None]* 
 *maildrop [None]* 
 >>/mbox<< 
   Yes 
   Yes 
     No 
  Yes 
   Yes 
  Yes 
  Yes 
 Yes 
 Yes 
 >>/mbx<< 
   No 
    Yes 
     No 
  Yes 
    No 
  Yes 
  No 
 No 
 No 
 >>maildir<< 
  Yes 
    No 
     Yes 
  Yes 
   Yes 
  No 
  Yes 
 Yes (3.22) 
 Yes 
 >>/mailstore<< 
   No 
    No 
     No 
  Yes 
    No 
  No 
  No 
 No 
 No 
 >>/dbox<< 
  Yes 
    No 
     No 
  No 
    No 
  No 
  No 
 No 
 No 
 >>/MH<< 
  No 
    Yes 
     No 
  No 
  No 
  Yes 
  Yes 
 Yes 
 No 


Conversion Between Mailbox Formats
==================================


See >>Migration/MailFormat<<. 


References
==========



 * Mutt mailbox formats: http://rucus.ru.ac.za/docs/mutt/manual58.html 
 * Article on mailbox formats: http://www.livejournal.com/users/rfunk/1571.html 
 * Mbox and maildir comparison: http://www.linux-mail.info/mbox-maildir-mail-storage-formats/ 

(This file was created from the wiki on 2007-12-11 04:42)
