Re: [Evolution] Mailbox formats

[Not Zed <notzed ximian com>]

I would just add:
 - i'd recommend mbox or maildir
 - do not use mh unless you are integrating with an existing
implementation

With newer filesystems, inodes and directory lookups are less of a
problem, and maildir becomes more attractive.  However, mbox still
scales pretty well to large mailboxes, depending on your disk speed.

A table of basic performance characteristics:
                 maildir       mh       mbox
open folder      medium        medium   fast   (depends on filesystem)
delete (expunge) fast          fast     slow
append           fast          fast1    fast
read message     fast2         fast2    fast

1: no locking, mh unreliable with concurrent accessors
2: can slow down with mailboxes with large numbers of messages on simple
filesystems, but is still relatively quick.

About the only other issue is that mbox files are limited to the maximum
filesize on the filesystem, which is typically 2GB.  So if you are
sending around a lot of big documents and keeping them in your mailbox,
maildir would make some sense (particularly since evo doesn't archive
yet).

> easy to work on with unix tools.  Mostly NFS safe - in that basic
> operations are defined in a way that is safe even without any locking,
> *but* more complex operations (rewrites) may hit limitations and require
> a degree of synchronisation.  Burns some space in that it uses a cluster

Well you should never rewrite messages, only rename them.