[CentOS] Converting to maildir

Tue Jan 4 15:38:47 UTC 2011
Jeff <jlar310 at gmail.com>

On Mon, Jan 3, 2011 at 7:17 PM, Jason Pyeron <jpyeron at pdinc.us> wrote:
> Looking for a guide on converting to Maildir.
> Here are our relevant specs.
> sendmail-8.12.11-4.RHEL3.6 (we may not be able to upgrade this due to too many
> modifications)
> imap-2002d-14
> procmail-3.22-10.el3.centos.0
> To a maildir setup...
> <rant>
> I was in a panic today at work because the backup server is filling up too
> quickly, backing up peoples email. Further it is not backing up often enough. I
> just lost all of today's email. I hate mbox and imap and outlook...
> </rant>
> All the maildir stuff I can find is postfix oriented. From what I can read in
> procmail man pages, it supports maildir and sendmail uses procmail as the LDA,
> hence sendmail "supports" it.
> -Jason

Regardless of the maildir vs mbox argument, I would be seriously
examining why you have painted yourself into a corner with your
customized sendmail. Eventually, you will have to move on. What are
the motivations for the customizations? Do newer or alternate MTAs
have added features that can replace those customizations? Postfix can
be highly customized through configuration and is not that difficult
to learn.

As a migration path, I would separate the MTA (sendmail) and the imap
server. Go with cyrus or dovecot on a new machine (virtual?) and use
imapsync to move messages to the new box during a maintenance window.
As stated in other responses, cyrus has it's own mail storage format
with individual files for each message and dovecot supports several
formats including maildir. It should not be difficult to have your
existing sendmail deliver messages to the new imap store either
directly or with a very simple postfix MTA on the imap box. Once mail
storage is fixed, you can start working on de-customizing your MTA.

And with regard to backup space, it might be time to suck it up and
tell your users that you need to implement mail quotas. How much are
you backing up from "Sent" and "Trash" because nobody maintains their
mail folders? A quota can be a great tool for teaching basic mail
folder housekeeping.