suggestion need to design an email system.

Adam Tauno Williams adam at
Wed Sep 17 10:49:27 EDT 2008

> I noticed that dovecot and cyrus don't differ that much in speed to
> each other. Both seem to excel at certain points, while being weaker
> at another. But overall the performance on a huge mailbox seemed to be
> comparable. Dovecot seemed to be slightly better at searching in the
> mailbox, esp.

Do you have SQUAT enabled on Cyrus?  Are you sure that the IMAP client
in question sends searches to the server (aka: not using Thunderbird)?

> What really intrigued me about dovecot was the ability to run on
> standard mailbox formats, which may not be much of an issue when
> running in a pure cyrus environment, but is a huge plus when migrating
> from another server. 

I don't see why it is an advantage for migration.  Tools like imapsync
don't care.

> Especially the "self-healing indexes" which were
> built on first use of a mailbox, and not using a reconstruct. So
> getting dovecot to run was very simple. And I like programs which take
> a common format, and don't think they need to re-invent the wheel.

I actually view this as a strong negative as it incentivises people to
muck about in the mailstore rather than using the tool-chain.   All
operations on a "real" server (IMO) should be performed via a tool and
not by hacking about beneath the service.

> And the last thing is SASL. Dovecot needs no SASL, it brings
> authenticators for a variety of sources, and offers postfix and exim
> auth mechs as well. This may be a very personal thing, but if I can
> work around SASL, I'm very, very glad about that. SASL may offer
> everything you may need in a century of running a mailserver, but
> getting it to run is just painful, and debugging is non-existant (at
> least the last time I tried to implement it, which is a couple of
> years ago. Since then I worked around the issue whereever I could).

Again, I just disagree.  Most SASL operations these days, "just work".
And when using something like GSSAPI SASL is a nicely known quantity.

Documentation of SASL is generally pretty bad, but hey, this is Open
Source.  In general *ALL* the documentation is crap. :)

> Cyrus has undisputed the broadest implementation of the IMAP protocol
> in the open source world, especially regarding shared folders. If you
> need that, there is no way around cyrus. It has a very broad user
> base, and has proven itsself to be quite solid in terms of scalability
> and stability. Dovecot has yet to prove that (at least to me).
> If I personally had the chance, I would give dovecot a shot, at least
> in a testing environment. But probably mostly out of curiosity, and
> because "Its new" ;) But except for the missing support for shared
> mail folders, I see no real reasons against dovecot, at least not for
> giving it a try.

Does Dovecot support:
 - Delayed expunge
 - Expiration (like ipurge)
 - Single-instance storage

Not that Cyrus couldn't do with some improvement.  The notifyd, which is
really interesting, is basically useless.  It would be very nice to have
a way to do push e-mail without polling mailboxes.   Neither, I believe,
offer any real reporting, via SNMP or any other mechanism so all
capacity planning involves crawling around the OS collecting various
statistics.  (I'm pretty sure Cyrus actually has some SNMP support, but
documentation is zero;  I also haven't looked in awhile).
> And please don't take this as a personal insult to all hardcore cyrus
> evangelist. I tried to be just and unbiased, and after all, it is MY
> PERSONAL OPINION. On this mailinglist, you don't need one more person
> voting for cyrus, there are enough of those........ ;)

Yep. :)

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