Replication verification

[David Carter]

On Fri, 27 Jun 2008, Vladimir Klejch wrote:

> I searchig for a  posibility to  use both server's in production as
> master-master.

Afraid that replication in Cyrus doesn't support full master-master, only 
master/slave. UIDs in IMAP make full master-master rather involved. It is 
possible to run a mix of master and replica mailstores on a single system.

> There are tools like nake_md5 and make_sha1, but the manpages document 
> only howto config them, but not how to realy use them for replication 
> check.

I download the md5 files to a single location and run a 50 line Perl 
script to spot mismatches. You are welcome to a copy of that script.

To make sure that the replica is up to date I run sync_client in an extra 
verbose mode (-v -v) and check for unexpected updates. Unfortunately that 
code didn't make it it into the vanilla Cyrus tree because of the 
reorganisation required to run sync_server from master using prot streams 
for communication. It wouldn't take a huge amount of effort to add "-v -v" 
into standard Cyrus.

I believe that Fastmail have an external test suite which does spot checks 
on the master and replica versions of each account. This is the opposite 
approach, and makes sense if you have a convenient IMAP client library.

-- 
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.