IMAP Server: Cyrus vs Dovecot
 

Hi there!
We've been on Cyrus IMAP since 2006, Version 2.3.
Now I need to set up a new server and migrate the mails from the old server. So I need to choose weather to migrate to Cyrus or to Dovecot.
I'd like to stay on Centos (6.6). I managed to compile and configure the Cyrus 2.5.3 but am having some problems in my lab with migrated content so was thinking why not check what's out there and see if there is a better solution.

My experience with Cyrus:

I like the process I have with cyrus: I enter the user on my FreeRadius Server, Cyrus uses PAM to check password, if match then Cyrus creates the inbox if not already existing. I then manually add user to /etc/group for the permissions I want him to have (since the mailbox ACLs are assigned to the groups).
So the priocess works, but it's very bad documentation and that seems to be more important now as we need more people being able to maintain the stuff.
We have some 2500 Mailboxes (most of them public/shared), 40 Users. Not very much, performance is currently not an issue. Using Maildir++ format.

What I've heard about Dovecot is he can do almost all the stuff as cyrus, but better documented.
I've played with Dovecot a bit, but now I have a few questions:
- can Dovecot be set up so he polls PAM (FreeRadius in my case) for userdb as well, not only passdb? Wiki mentions PAM only for passdb.
- do ACL work similar to Cyrus? I assign users to groups and groups to public folders? Some need to be able to read the messages, some to delete and some to move new messages to folder.
- we need sieve implementation for autoresponder/vacation and for moving marked mails to spam folders. That should be no problem, right?

Most important:
- if I go with Dovecot, I'd need to migrate the mails, mailboxes, permissions and seen-states... and stuff you have when you mark mails as "important", "work", "personal", and star them in Thunderbird. I don't know if it's client side info or server-side. So would it be possible to migrate and preserve all the information? Can Cyrus2Dovecot preserve all the stuff?

I've lost a lot of time trying to set up cyrus, so now I'm asking your help so I figure out which way to go from here.

TIA

Choosing between Cyrus vs Dovecot

To try to help at least with the first part of the question, it has more to do with preferences.

- You already have experience with Cyrus, how comfortable are you with Dovecot?
- Dovecot is more common, more people would be familiar with it.
-- What are the odds of other administrators needing to manage the server, such as you leaving for a different job and another administrator takes over.
-- More sources of support of Dovecot since it is more commonly used.
- If you are using any kind of admin access software (Plesk, Ensim, cPanel, ect) is Dovcot on their compatibility list?

Some of the other questions you are asking can only be done by tackling each one during an actual migration. As this is a large scale production server I would not suggest doing it live, but rather have a copy on a test server to run the migration on and then do a cut over.

Hi Joe!

Yes, I have expirience with Cyrus, none with Dovecot. But I cannot afford to be the only one in the company to handle that stuff so documentation and supportability (community) became a big criteria. We need to meet certain demands though (the ones I listed).
I use no admin access software, it's just sasldpasswd2 to create an account and cyradm for creting/deleting mailboxes and permissions. We need to move to some centralized solution (LDAP, AD, MySQL, Radius...) though.

Today I also started to look at Exchange (again). I discarded Exchange earlier because I thought it's not as flexible as IMAP (without having to setup Sharepoint & Co), but that's probably very dangerous thing to say at least somewhere out of linuxquestions.org forum :D.

Thanx & bye

Hopefully others might join this thread, but just running a quick search I ran across some interesting information:

Dovecot V1 Migration Cyrus
http://wiki.dovecot.org/Migration/Cyrus

Dovecot V2 Migration Cyrus
http://wiki2.dovecot.org/Migration/Cyrus

Dovecot Support - IRC - Mailing List - ect
http://dovecot.org/support.html