Paying for developers?

[David Carter]

On Tue, 14 Sep 2004, Attila Nagy wrote:

>> http://www-uxsup.csx.cam.ac.uk/~dpc22/cyrus/replication.html
> There are some problems with that:
> - the code isn't available on that webpage

No, but the code is available to people who want to play with it on the 
understanding that they get no sympathy from me if they try and run it on 
a production server right now.

> - it changes the mailstore layout, so you cut off yourself if you use that 
> instead of the mainstream version

The incompatible change is actually just a single 96 bit value per message 
in the cyrus index file (a message UUID value, used to replicate the 
single instance store). If a future UUID format was agreed and space was 
reserved in current index files, the incompatibility would disappear. That 
might be a path to more widespread testing.

> - I guess it is for an older Cyrus, so you cannot easily upgrade

I passed a patch relative to 2.3 CVS on to Rob a few months back. The 
replication code is largely orthogonal to the existing code: it only took 
me a couple of hours to generate the patch from my existing 2.1.16 code.

> I cannot say anything about its architectural problems, if there are any 
> at all.

I consider the code to be a prototype of the "obvious" way to do 
application level replication in Cyrus. It works fine for us, but would 
clearly require a careful audit before going into more widespread use.

Support for a number of things is missing simply because we have no need 
for them right now: seen state handling for shared mail folders, quota 
roots other than user.<whatever>, and in 2.2+ mailbox annotation and 
virtual domains spring to mind. I don't think that any of these things 
would be particularly hard to do, its just a Small Matter of Programming.

I would estimate that I've put in about around 3 to 4 months work on the 
current code and that we would be talking about (at least!) several more 
man months work between myself and Cyrus developers to get something 
properly merged. Thats a fairly substantial undertaking for all involved, 
particularly given that we all have other priorities.

-- 
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.
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