I read somewhere that you should always have an odd number of nodes in your cluster, because of the galera quorum mechanism.
How does this work in XtraDB Cluster.
I want to have an 8 node cluster, with 4 nodes in each datacentre.
HAproxy on each webserver (which are also split across datacentres) will balance the load across the cluster.
But the likely scenario is that 4 servers will ‘disappear’ if one datacentre ‘goes down’. This means that there will still be an even number of nodes remaining. Will the XtraDB cluster handle this gracefully? And how would it work? Or do I need a garbd server in there somewhere?