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Re: Mirror Mode, MMR and replicas

--On Wednesday, March 18, 2009 10:18 PM +0100 Rein Tollevik <rein@OpenLDAP.org> wrote:

Quanah Gibson-Mount wrote:
--On Wednesday, March 18, 2009 3:01 AM -0700 Howard Chu <hyc@symas.com>

I'll start with replication under MMR.

As I understand it, the replicas can only point at a single master.


Last I checked, the provider parameter in the syncrepl configuration block was single valued. Which means either it gets pointed at a load balancer, or it only talks to a single master. If that master goes down, it no longer talks to anything without reconfiguration.

Each syncrepl engine (configuration block) can only refer to a single master, but you may configure many engines within the same database, each with its own master. If one master goes down the engine using that master will obviously not receive any updates until its master is up again, but the other will continue to receive updates from their master.

Ok, this was the point I didn't realize -- That syncrepl on a replica will correctly handle looking at two masters providing the same changes to it.



Quanah Gibson-Mount
Principal Software Engineer
Zimbra, Inc
Zimbra ::  the leader in open source messaging and collaboration