[OpenAFS] Re: maildir on openafs [new faq entry]

Adam Megacz megacz@hcoop.net
Tue, 08 Apr 2008 12:51:29 -0700

"David Bear" <David.Bear@asu.edu> writes:
> I seem to distantly recall some discussion about storing maildir directories
> on openafs, but I don't remember if it was safe, discouraged, or otherwise
> problematic. Any one see problems with putting maildir in afs?

HCoop is doing this with courier, and it works, although the gadgetry
currently used to acquire tokens is really, really sketchy.

Many users really like having shell access to their mailbox, backup
volumes of their mail, the ability to grep their mail, etc.

The (sole) SMTP server, (sole) IMAP server, and AFS fileserver all
happen to be the same (fairly powerful) machine, so we may be dodging
some of the performance issues that other people see.

Robert Banz <rob@nofocus.org> writes:
> Its a mess.  AFS is not for mail. Unix "user accounts" are not for
> mail.  Use an actual mail system and do it right ;)

This sentiment comes up here often, and although there is much truth
in it, I think that stating it so dogmatically might not be the most
productive route to take.  Mail uses storage; AFS provides storage;
so, let's not imply that putting mail in AFS is obviously stupid!
(perhaps it's only non-obviously stupid).

The problems, as I am aware of them, are:

  - AFS does not perform well under the sort of multiple-machine
    concurrent access scenario that certain mail architectures
    (large-site Cyrus) use.

  - Unlike POP, the IMAP protocol offers many features which are best
    implemented by backend storage which is more database-like than
    filesystem-like in nature.  AFS is a less than ideal storage
    medium for databases, for reasons explained elsewhere.

Anyways, I've started a FAQ entry to collect concrete reasons why mail
should or should not be stored in AFS.


I will update the FAQ entry with the proceeds of this thread; please
share your reasoning for encouraging or discouraging mail in AFS.

  - a