Introduction

This article details the proper method of load balancing either a Percona XTRADB Cluster (PXC) or MariaDB Cluster.  Both of these solutuions utilize the same Galera plugin to facilitate clustering.  This information deatails what ports must be open and how they are to be configured as well as how to route traffic to the database nodes.

There are generally a total of three (3) nodes in this cluster, along with a single load balancer. This is the minimum number of nodes required for a cluster. This does not mean that the cluster is down if one or two nodes are lost – it only means that at least three nodes are required for normal cluster operation.

Data Centers

One of the most common questions we receive is whether the cluster can span two data centers.  The short answer is “Yes, but…”   While it is possible for a cluster to span two data centers, it …