Where are the logs for a Tungsten Cluster and which are the proper log files to monitor if I do a master role switch to another node?
When deploying Tungsten Clustering for MySQL / MariaDB / Percona Server, we always recommend an odd number of Manager nodes in each cluster. Let's take a look at how having an odd number of Managers helps keep a Tungsten Cluster functioning and avoids data corruption scenarios (i.e. "split brain").
You already know about the Tungsten Connector which is the "secret sauce" that routes your application database traffic to the appropriate MySQL data source of your cluster. Have you ever wondered how the Connector keeps track of the cluster configuration? How it always knows which host is the master (or masters in a Composite Multimaster topology), and which are slaves?
Over the years, Tungsten Clustering has grown and matured. Early on, in response to our customers' needs, we introduced the concept of the Passive Witness to allow for clusters with only two nodes. Normally, a cluster requires three nodes to create a voting quorum, which requires an odd number of members to avoid split-brain scenarios. It is the Witness which provides the tie-breaker in the event of a network partition.
