Quanah Gibson-Mount wrote:I think it's a strong plus to be able to reconfigure a standalone server into an MMR cluster with zero downtime,I don't buy this argument. If you're really eager reaching high availability you have to implement a decent load-balancer and test correct fail-over anyway. And then your MMR cluster will have zero down-time (seen from the LDAP clients) during re-configuration even when restarting the replicas one after another.
I'm talking about the process of taking a single provider + multiple replicaenvironment and trivially transitioning that to an MMR environment, where it can either be a mix of providers and replicas, or all providers, etc. With the replicas configured to pull from 1+ providers. You can do that entire transition via cn=config with no downtime. With slapd.conf, you will have to stop the provider (outage) to reconfigure it into an MMR capable scenario. And I've never needed a load balancer with properly written software that understands how to parse multiple LDAP URI's for failover.
--Quanah -- Quanah Gibson-Mount Product Architect Symas Corporation Packaged, certified, and supported LDAP solutions powered by OpenLDAP: <http://www.symas.com>