High-Availability IMAP server

[David Carter]

On Mon, 26 Sep 2005, Aaron Glenn wrote:

> There is replication code in the 2.3 branch; though from what I can tell 
> it hasn't been touched in a few months and makes me wonder if it's being 
> actively developed still. Nevertheless, in my exhaustive search for any 
> and all information on IMAP replication, I came across a few list posts 
> detailing the 2.3 replication code in production, without many issues, 
> for over a year.

I wrote the code which was eventually merged into the 2.3 branch back in 
Autumn 2002. We've been using it on our production systems for a little 
over two years now, and all of our users have been replicated (rolling 
replication to hot spare system, plus nightly replication to tape spooling 
array) for about 18 months.

The last significant change to my code base was November last year. That's 
not a sign of neglect, the code just does everything we need right now.

Ken merged the code into 2.3 at the start of this year. He put in quite a 
lot of work to merge the code properly into Cyrus (I had deliberately left 
it to one side to make updates easier) and add support for features such 
as shared mailboxes and annotation that we just don't need right now. Its 
still conceptually the same code and the same design.

Invariably working on code introduces new bugs (including a particularly 
exciting one caused by a stray semicolon). People are also pushing the 
code in new and interesting ways. Ken fixed a bug involving account 
renaming (user.xxx -> user.yyy) a couple of weeks back: that's something 
our nightly useradmin scripts just never try to do.

Looking back at features which were introduced into earlier versions of 
Cyrus, I imagine that people will start to test the new code seriously 
when Cyrus 2.3 is released, and that there will be a period of fixing bugs 
which will tail off as 2.3 stabilises.

The complication is that there doesn't appear to be anyone left at CMU to 
release new versions of Cyrus at the moment. Poor Jeffrey Eaton seems to 
be the last man standing there. My own experience of running things single 
handed is that it doesn't leave much time for development work.

-- 
David Carter                             Email: David.Carter at ucs.cam.ac.uk
University Computing Service,            Phone: (01223) 334502
New Museums Site, Pembroke Street,       Fax:   (01223) 334679
Cambridge UK. CB2 3QH.