How nodes work in ElasticSearch Cluster

Question

I have a cluster of 4 nodes.

Node 1: node.master: true node.data: true Node 2: node.master: true node.data: true Node 3: node.master: true node.data: true Node 4: node.master: false node.data: false

and discovery.zen.minimum_master_nodes: 2.

Now, as per my understanding, there will be single master elected for the cluster and the master decides where and how to store the incoming data.

Say suppose, Node 2: goes down and never comes back. The cluster will still be up and running as reelection takes place when Node 2: goes down.

But what happens to the data which was stored in Node 2:. Can any one please explain me the flow here.

Answer 1

If node 2 goes down and never come back means you lost the data forever, unless you have replica configured.

If you have one replica for each shard, then you will have extra copy of each shard in different node.

So when node 2 goes down, the node 2 data will server from replica server from node 2 or node 1.

Hope it helps!