1 This file points out some reasons that you might want to switch from

     2 mbox format to a new format, maildir.

     3 

     4 

     5 1. The trouble with mbox

     6 

     7 The mbox format---the format of ~user/Mailbox, understood by BSD Mail

     8 and lots of other MUAs---is inherently unreliable.

     9 

    10 Think about it: what happens if the system crashes while a program is

    11 appending a new message to ~user/Mailbox? The message will be truncated.

    12 Even worse, if it was truncated in the middle of a line, it will end up

    13 being merged with the next message! Sure, the mailer understands that it

    14 wasn't successful, so it'll try delivering the message again later, but

    15 it can't fix your corrupted mbox.

    16 

    17 Other formats, such as mh folders, are just as unreliable.

    18 

    19 qmail supports maildir, a crashproof format for incoming mail messages.

    20 maildir is fast and easy for MUAs to use. Even better, maildir works

    21 wonders over NFS---see below.

    22 

    23 I don't want to cram maildir down people's throats, so it's not the

    24 default. Nevertheless, I encourage you to start asking for maildir

    25 versions of your favorite MUAs, and to switch over to maildir as soon as

    26 you can.

    27 

    28 

    29 2. Sun's Network F_ail_u_re System

    30 

    31 Anyone who tells you that mail can be safely delivered in mbox format

    32 over NFS is pulling your leg---as explained above, mbox format is

    33 inherently unreliable even on a single machine.

    34 

    35 Anyway, NFS is the most unreliable computing environment ever invented,

    36 and qmail doesn't even pretend to support mbox over NFS.

    37 

    38 You should switch to maildir, which works fine over NFS without any

    39 locking. You can safely read your mail over NFS if it's in maildir

    40 format. Any number of machines can deliver mail to you at the same time.

    41 (On the other hand, for efficiency, it's better to get NFS out of the

    42 picture---your mail should be delivered on the server that contains your

    43 home directory.)

    44 

    45 Here's how to set up qmail to use maildir for your incoming mail:

    46 

    47    % maildirmake $HOME/Maildir

    48    % echo ./Maildir/ > ~/.qmail

    49 

    50 Make sure you include the trailing slash on Maildir/.

    51 

    52 The system administrator can set up Maildir as the default for everybody

    53 by creating a maildir in the new-user template directory and replacing

    54 ./Mailbox with ./Maildir/ in /var/qmail/rc.

    55 

    56 Until your MUA supports maildir, you'll probably want to convert maildir

    57 format to (gaaack) mbox format. I've supplied a maildir2mbox utility

    58 that does the trick, along with some tiny qail and elq and pinq wrappers

    59 that call maildir2mbox before calling Mail or elm or pine.