The transition was quick, and also (so far) seemingly painless.

The server is an old Pentium II 233 machine that sits between my home LAN and the internet, and have sitting there, and running night and day since 1999. For the first two years it was running SuSE linux, but since 2001 it has been running debian and been continously upgraded. It was originally installed with potato, but have been apt-get dist-upgrade'd to woody, and then to sarge, and then etch, which is what it's currently running

I've been using cyrus imapd since 1999 (compiled by hand on SuSE and using the debian packaged version on debian).

But in all these years I've never become really friendly with it. In the years leading up to 1999 I had been running UoW imapd at work, and I wasn't too impressed with it at that point in time. The alternative choices were courier and cyrus, and I picked cyrus more or less arbitrarily.

By "never become really friendly", I mean

• I've never really gotten a good understanding of the configuration
• I've never quite understood what the documentation have said about authentication and SSL support. I've gotten things to work by trial and error
• Four times the seen data bases have become corrupt. Two times during upgrades (one of them after I had switched to skip lists), and two times on their own, while I was still running BDB
• Since delivery was to a central spool and database, owned by user cyrus, has meant that I had to use sieve (which is another thing I've never quite understood) for mail filtering, instead of dear old procmail

Cyrus has lots of stuff related to scaling and having mailboxes for users that have no users on the host, but that's not really relevant to my home server.

Around six months ago I stumbled over dovecot, which from my POV have the following crucial features:

1. folders under the users' home directories, either as mbox or as maildir, which allows me to do list filtering with procmail, and no central databases that can become corrupt
2. understandable configuration (the only change I'd had to do in the debian dovecot, is to allow for cram-md5 authentication)

I decided om maildir as the folder format. I like the simplicity of mbox folders, but I have some archive folders with around 20k of articles each, and maildir would scale a bit better for them. Also mail delivery without locking is a very nice feature.

Here's how I proceeded:

• I set up dovecot on my daughter's Ubuntu Hardy machine
• I ran imapsync on this machine to extract everything I had on the cyrus server to Maildir folders in the users' home directories on the Ubuntu box
• I shut down fetchmail on my gateway box (since ISP port filtering and blacklisting of dynamic addresses stops direct SMTP delivery I have to use ISP gateways and mail drops)
• I changed the exim conf on my gateway from using cyrdeliver to delivering to a maildir folder in the users' home directory
• I restored my old .procmailrc file from subversion (my home directory is checked into subversion, this was originally a CVS repo that went subversion a couple of years ago), merged in the last version of the .procmailrc that used cyrdeliver (I gave up on that because the .procmailrc file had to be owned by user cyrus, which was very impractical), and changed the filtering rules to deliver to maildir folders
• I tested some delivery
• I apt-get install'd dovecot from the etch back ports pointed to from the dovecot install page http://wiki.dovecot.org/PrebuiltBinaries#head-477d52d96fcf34ad3033b13e5e5a26... This uninstalled cyrus22-imapd, but not the rest of cyrus 2.2, which blocked dovecot from starting after the install
• I stopped cyrus22 and uninstalled all of the cyrus22 packages
• I rsync'd the maildir folders from the Ubuntu box to the old mail server
• I started dovecot
• I use Gnus as my MUA. I had removed all nnimap groups related to the home server in Gnus, and resubscribed them. All folders came up in the state I had left them. Gnus stores article state on the server as custom marks, and imapsync had preserved the custom flags. I unsubscribed the groups to avoid article caching confusion, because imapsync changes the UIDs. However, all folders except INBOX had changed their names, so that didn't matter much
• I started fetchmail and sent som test emails, and observed that they ended up in the right Maildir folders, and that dovecot picked them up as expected

And today I accessed the server from work. So it looks like I'm back in business. This time with a server I understand a lot better.

Thanx for writing it, Timo!

• Steinar