At this point replication of cn=config is broken and unsupported. 

However, we see miltiple Producers using MMR and Consumers added in using PCR (formerly Master/Slave Replication)  frequently. We recommend this kind of setup, particularly in geographically diverse architectures. It greatly reduces the amount of data traversing the WAN and reduces downtime for maintenance and upgrades. Delta-Syncrepl only further reduces the network load.

Jason Trupp

Pardon typos. Sent from smartphone.

-------- Original message --------
From: Ondřej Kuzník <>
Date: 10/18/18 5:44 AM (GMT-06:00)
To: Michael Ströder <>
Cc: Quanah Gibson-Mount <>, OpenLDAP Tehnical <>
Subject: Re: Adding read-only consumers to a Mirror Mode Replication setup?

On Thu, Oct 18, 2018 at 10:10:33AM +0200, Michael Ströder wrote:
> On 10/18/18 1:41 AM, Quanah Gibson-Mount wrote:
>> I've had setups with 2-node MMR on the front, and read only consumers. 
>> It works just fine, as long as any given consumer only points to one
>> master. Theoretically, it's supposed to work so that consumers can point
>> to more than one master in an MMR setup, but my experience didn't match
>> that (<>).
> There's no config in ITS#8373.
> But you mention accesslog DB.
> Does that mean your setup used delta-syncrepl?
> If yes, does that issue also apply to normal syncrepl?

I can see cn=config is being replicated in that ticket. It makes more
sense that the 'unwilling to perform' issue would be limited to
replicating the config (which can be more picky about its modifications)
rather than regular databases.

That kind of setup is being used in a significant number of deployments
and by Linus' law we'd have more reports like this one.

Ondřej Kuzník
Senior Software Engineer
Symas Corporation             
Packaged, certified, and supported LDAP solutions powered by OpenLDAP