1This file points out some reasons that you might want to switch from
2mbox format to a new format, maildir.
3
4
51. The trouble with mbox
6
7The mbox format---the format of ~user/Mailbox, understood by BSD Mail
8and lots of other MUAs---is inherently unreliable.
9
10Think about it: what happens if the system crashes while a program is
11appending a new message to ~user/Mailbox? The message will be truncated.
12Even worse, if it was truncated in the middle of a line, it will end up
13being merged with the next message! Sure, the mailer understands that it
14wasn't successful, so it'll try delivering the message again later, but
15it can't fix your corrupted mbox.
16
17Other formats, such as mh folders, are just as unreliable.
18
19qmail supports maildir, a crashproof format for incoming mail messages.
20maildir is fast and easy for MUAs to use. Even better, maildir works
21wonders over NFS---see below.
22
23I don't want to cram maildir down people's throats, so it's not the
24default. Nevertheless, I encourage you to start asking for maildir
25versions of your favorite MUAs, and to switch over to maildir as soon as
26you can.
27
28
292. Sun's Network F_ail_u_re System
30
31Anyone who tells you that mail can be safely delivered in mbox format
32over NFS is pulling your leg---as explained above, mbox format is
33inherently unreliable even on a single machine.
34
35Anyway, NFS is the most unreliable computing environment ever invented,
36and qmail doesn't even pretend to support mbox over NFS.
37
38You should switch to maildir, which works fine over NFS without any
39locking. You can safely read your mail over NFS if it's in maildir
40format. 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
42picture---your mail should be delivered on the server that contains your
43home directory.)
44
45Here's how to set up qmail to use maildir for your incoming mail:
46
47   % maildirmake $HOME/Maildir
48   % echo ./Maildir/ > ~/.qmail
49
50Make sure you include the trailing slash on Maildir/.
51
52The system administrator can set up Maildir as the default for everybody
53by creating a maildir in the new-user template directory and replacing
54./Mailbox with ./Maildir/ in /var/qmail/rc.
55
56Until your MUA supports maildir, you'll probably want to convert maildir
57format to (gaaack) mbox format. I've supplied a maildir2mbox utility
58that does the trick, along with some tiny qail and elq and pinq wrappers
59that call maildir2mbox before calling Mail or elm or pine.
60