Excerpts from Jay Pipes's message of 2017-05-30 14:52:01 -0400: > Sorry for the delay in getting back on this... comments inline. > > On 05/18/2017 06:13 PM, Adrian Turjak wrote: > > Hello fellow OpenStackers, > > > > For the last while I've been looking at options for multi-region > > multi-master Keystone, as well as multi-master for other services I've > > been developing and one thing that always came up was there aren't many > > truly good options for a true multi-master backend. > > Not sure whether you've looked into Galera? We had a geo-distributed > 12-site Galera cluster servicing our Keystone assignment/identity > information WAN-replicated. Worked a charm for us at AT&T. Much easier > to administer than master-slave replication topologies and the > performance (yes, even over WAN links) of the ws-rep replication was > excellent. And yes, I'm aware Galera doesn't have complete snapshot > isolation support, but for Keystone's workloads (heavy, heavy read, very > little write) it is indeed ideal. >
This has not been my experience. We had a 3 site, 9 node global cluster and it was _extremely_ sensitive to latency. We'd lose even read ability whenever we had a latency storm due to quorum problems. Our sites were London, Dallas, and Sydney, so it was pretty common for there to be latency between any of them. I lost track of it after some reorgs, but I believe the solution was to just have a single site 3-node galera for writes, and then use async replication for reads. We even helped land patches in Keystone to allow split read/write host configuration. __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev