Another 2.4 upgrade horror story

[Deniss]

On 2012.09.26. 10:24, Sebastian Hagedorn wrote:
> Hi,
> 
> I've got questions regarding the procedure you describe. I'm trying to
> wrap my head around the various possible approaches to replication and
> clustering.
> 
> --On 25. September 2012 21:57:49 +0300 Deniss <cyrus at sad.lv> wrote:
> 
>> migration process from 2.3 to 2.4 took ~ one year for our installation.
>> we converted ~200Tb of users data.
>> first step we did - spread data on many nodes using cyrus replication.
> 
> The official documentation for replication seems to be this one:
> 
> <http://cyrusimap.web.cmu.edu/docs/cyrus-imapd/2.4.0/install-replication.php>
> 
> 
> The way I read that, replication is all or nothing. So did each of the
> nodes have the whole 200 TB? If not, how did you achieve that? Did you
> have a murder with multiple backends to begin with?

Our system's design allows us to seamless move mailboxes across cyrus
backends one by one using sync_client. We have no murder.
Each node had relatively small list of mailboxes when we started convert
on it. After convert we aggregate mailboxes back.

> 
>> next we started converting nodes one by one at weekends nights to
>> minimize IO load generated by users.
> 
> How does replication work across Cyrus versions? I assume it wouldn't
> have been possible to create a new 2.4 replica from an existing 2.3 master?

it not works

> 
> Thanks, Sebastian