Cyrus Replication Rewrite

[David Carter]

On Fri, 29 Jun 2012, ktm at rice.edu wrote:

> I do not know if it is even possible, but can the implementation support 
> replication FROM an older release of Cyrus. This would really, really 
> help with the upgrade process. We are currently stuck on 2.3.x because 
> of the upgrade resource needs even though we have an essentially idle 
> replica that could easily handle the I/O of the upgrade, if only it 
> could be done on the replica while still streaming from the primary. I 
> know the ship has sailed for 2.3 -> 2.4 but it would be really nice to 
> have that feature going forward.

I ported my original Cyrus 2.1 replication code (which Ken Murchison 
rewrote for 2.3) to both 2.3 and 2.4 in order to be able to do seamless 
upgrades and downgrades by just migrating accounts around the cluster.

It is a really nice way to managing upgrades compared to scary one way 
Cyrus index upgrades. It does however require the two ends to be speaking 
the same or compatible replication protocol, and that is hard work if you 
are adding new features.

We now use the native Cyrus 2.4 replication code which is _much_ nicer 
than my original 2003 era code.

-- 
David Carter                             Email: David.Carter at ucs.cam.ac.uk
University Computing Service,            Phone: (01223) 334502
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