64 lines
2.7 KiB
Text
64 lines
2.7 KiB
Text
This file points out some reasons that you might want to switch from
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mbox format to a new format, maildir.
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1. The trouble with mbox
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The mbox format---the format of ~user/Mailbox, understood by BSD Mail
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and lots of other MUAs---is inherently unreliable.
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Think about it: what happens if the system crashes while a program is
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appending a new message to ~user/Mailbox? The message will be truncated.
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Even worse, if it was truncated in the middle of a line, it will end up
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being merged with the next message! Sure, the mailer understands that it
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wasn't successful, so it'll try delivering the message again later, but
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it can't fix your corrupted mbox.
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Other formats, such as mh folders, are just as unreliable.
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qmail supports maildir, a crashproof format for incoming mail messages.
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maildir is fast and easy for MUAs to use. Even better, maildir works
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wonders over NFS---see below.
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I don't want to cram maildir down people's throats, so it's not the
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default. Nevertheless, I encourage you to start asking for maildir
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versions of your favorite MUAs, and to switch over to maildir as soon as
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you can.
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WARNING: qmail uses flock() to lock ~user/Mailbox. This agrees with the
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modern mail.local locking choice. If your MUA doesn't use flock(), your
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best bet is to switch to maildir, and to set up synchronous maildir2mbox
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execution, as described below.
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2. Sun's Network F_ail_u_re System
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Anyone who tells you that mail can be safely delivered in mbox format
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over NFS is pulling your leg---as explained above, mbox format is
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inherently unreliable even on a single machine.
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Anyway, NFS is the most unreliable computing environment ever invented,
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and qmail doesn't even pretend to support mbox over NFS.
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You should switch to maildir, which works fine over NFS without any
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locking. You can safely read your mail over NFS if it's in maildir
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format. Any number of machines can deliver mail to you at the same time.
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(On the other hand, for efficiency, it's better to get NFS out of the
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picture---your mail should be delivered on the server that contains your
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home directory.)
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Here's how to set up qmail to use maildir for your incoming mail:
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% maildirmake $HOME/Maildir
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% echo ./Maildir/ > ~/.qmail
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Make sure you include the trailing slash on Maildir/.
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The system administrator can set up Maildir as the default for everybody
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by creating a maildir in the new-user template directory and replacing
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./Mailbox with ./Maildir/ in /var/qmail/rc.
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Until your MUA supports maildir, you'll probably want to convert maildir
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format to (gaaack) mbox format. I've supplied a maildir2mbox utility
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that does the trick, along with some tiny qail and elq and pinq wrappers
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that call maildir2mbox before calling Mail or elm or pine.
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