[TriLUG] Imap software preferences

[John Franklin]

On Sun, Aug 04, 2002 at 10:31:18PM -0400, Tanner Lovelace wrote:
> Now that we have the ldap/kerberos server up and running (it will
> be going into the rack tomorrow), it's time to turn to getting
> the imap server up and running.  Cyrus imap was previously
> suggested but after looking at it and setting it up once, I'm
> not convinced it's the best idea.  If I go with one of the standard
> imap servers, we could nfs mount home directories (on an internal
> network so it's not going over the public network) and allow
> everyone to use procmail to process their e-mail.  What I'd like,
> however, is people's opinions on the various imap servers.  I've
> run the washington imap server on my own server forever and am
> very familiar with it.  I've also heard, though, many people
> disparage it.  I know Courier imap uses the maildir format, but
> that's about it.  Does anyone have any preference for imap server?
> Speak now and forever hold your peace. :-)

If memory serves me right, the Cyrus server may be faster, but it puts
all the mail in a database that's understood by only Cyrus.  Which means
that even on the IMAP server we have to use IMAP to get mail.

Maildir format is understood directly by a handful of mail clients. It
keeps every message in a separate file.  Does the standard subdivide the
mail folder?  That is, does it limit a directory to, say, 500 messages
then start a new sub-folder?  Large directories put strain on ext2/3 and
other UFS derived file systems.  The directories are kept as an unsorted
linear list.  In order to do a create, the entire list must be traversed
to insure the filename doesn't already exist.  It also means that every
message will take up at minimum 1 fragment (typically 1k or 4k.)

Mailbox format, as supported by the vast majority of mail clients and UW
IMAP, is a single file per user.  Large mailboxes can take time to scan.
I think UW mmap()s the mailbox, which means they don't get swapped to
the swap partition.  In case anyone cares, UW IMAP also comes with a
pop server.

I've been running UW on elfie for years without a hitch.  (I know I'm
not going to be running the TriLUG server.  This is just an empirical
data point.)  Tanner has been running UW since forever, may/will admin
the box and doesn't seem to poo-poo UW.

Any of them can be SSL'd though sslwrap.

Easy migration.  Well known.  Widely compatible.  My vote is for UW
IMAP.

jf
-- 
John Franklin
franklin at elfie.org
ICBM: 35°43'56"N 78°53'27"W