Mailbox formats

The following are some notes about different mailbox formats. Please feel free to share your comments, suggestsions, fixes and links.

Links

Benchmarking mbox versus maildir
http://www.courier-mta.org/mbox-vs-maildir/

Mailbox Format Characteristics
http://www.washington.edu/imap/documentation/formats.txt.html

maildir(5) manual page (from qmail)
http://www.qmail.org/qmail-manual-html/man5/maildir.html

Using maildir format
http://cr.yp.to/proto/maildir.html

mbox(5) manual page (from qmail)
http://www.qmail.org/qmail-manual-html/man5/mbox.html

CPAN's MailFolder Perl module
http://theoryx5.uwinnipeg.ca/CPAN/data/MailFolder/

Mailbox formats (from Mail-Administrator HOWTO)
http://linuxdocs.org/HOWTOs/Mail-Administrator-HOWTO-3.html#ss3.5

mbox

Also called "standard Berkeley format". This is the default Unix mailbox format as defined by mail.local(8): 
     Individual mail messages in the mailbox are delimited by an empty line
     followed by a line beginning with the string ``From ''.  A line contain-
     ing the string ``From '', the sender's name and a time stamp is prepended
     to each delivered mail message.  A blank line is appended to each mes-
     sage.  A greater-than character (``>'') is prepended to any line in the
     message which could be mistaken for a ``From '' delimiter line.
mbox is consider by some to be bad.

MBX

MBX is basically a indexed mbox format. Opening a MBX mailbox with a 1000 messages is much faster than opening MailDir mailbox with a 1000 messages. (Any proof/benchmarks?) mbx is used in UW-IMAP / c-client.

Maildir

Maildir may be slow if the mailbox contains many different messges. The directory has be opened, and each file (message) must be opened to get the header information. (For ext2 filesystem, it is said that performance starts getting slow at around 10,000 files per directory.) Maildir's may require a lot of inodes. Some say maildir is significantly better than mbox.

mh folders

?