DoveCot vs Cyrus-Imapd Performance

[Aleksandar Milivojevic]

Ow Mun Heng wrote:
> Hi All,
> 
> 	searching my of-line fedora list archive (535271 mails) around did not
> give me any information on the performance difference between using
> dovecot and using cyrus.
> 
> Right now, I've installed and configured postfix and cyrus-imapd to
> handle only 2 email accounts. (testing)
> 
> I recently had a chat with a friend and he was telling me dovecot is
> turning out to be not only simpler in configuration but was also
> faster(?) than cyrus-imapd.
> 
> To Run a imap server serving say a big corporation, heck even a _big_
> ISP, which would have been better? Cyrus or dovecot? Has anyone any
> experience with running both and testing/playing with either?

Some people say Cyrus is complicated to manage, but I disagree.  To use 
Cyrus on Fedora, simply install Cyrus packages, change two lines in 
sendmail.mc, and off you go.  It simply works.  You don't need to touch 
anything.

The only administration overhead compared to wu-imapd or dovecot, you 
have to manually create user's mailbox (using cyradm).  Now, how 
complicated is to type "cm user.foobar"?  I wouldn't call that something 
complicated.  If you are to lazy to type "cm user.foobar", you can just 
as well use autocreateinboxfolders and autosubscribeinboxfolders options 
in imapd.conf, and have Cyrus do the job for you, mailboxes will be 
created automatically as soon as user logs in.  Can it be any simpler? 
Probably not. (as a side note, my advice is not to use createonpost in 
combination with auto*inboxfolders options, or you'll get mailbox 
created for every mistyped email address).

If you don't want users to have shell accounts just change setting for 
saslauthd in /etc/sysconfig/saslauthd to use something other than shadow 
file for authentication (pam/ldap/kerberos5/whatever).  Simple as that.

For large coprporation / big ISP, Cyrus is probably easier to implement 
and manage.  In those kinds of places, you don't want users to have 
accounts on the mail server (Cyrus is designed not to require local user 
accounts from day one).  You also need a way to enable users to setup 
forwarding, vacation messages, and maybe even server-side mail filtering 
without using home directories with .forward and/or .procmail files on 
local file system.  All of those come out of the box and working with 
Cyrus IMAPD.  All you need to do is setup some kind of Web interface for 
users to use (such as for example smartsieve or websieve -- it would be 
nice if one of those two was packaged with Fedora).  Installing 
smartsieve on Fedora is 10-15 minute job even for novice sysadmin 
(including time needed to use Google to find it on the web, and download 
it over not-so-fast link).  If you can't do it in 15 minutes, step down 
from pedestal and stop calling yourself sysadmin ;-)

The only thing that is more complicated, IMHO, is if you already have 
users, and mail folders are in different format.  Than you need to 
migrate it into the Cyrus.  This can be time consuming if you have huge 
userbase (say 100,000 or more users).  It requires a bit of planning, 
but is kind of straight forward.  For some ideas (and ready-to-use 
conversion tools) check out:

http://www.oreilly.com/catalog/mimap/chapter/ch09.html#92594

Other than that, Cyrus IMAPD is only as complicated as you choose to 
make it complicated.  If you intend to keep it simple, it will be 
simple.  If you need to make complicated setup, it will allow you to do 
so.  But than, it was you that complicated the things, not the Cyrus.

-- 
Aleksandar Milivojevic <amilivojevic at pbl.ca>    Pollard Banknote Limited
Systems Administrator                           1499 Buffalo Place
Tel: (204) 474-2323 ext 276                     Winnipeg, MB  R3T 1L7