I am trying to reindex 20million documents(size of 5 TB) from kibana console using re-index api. After only little over 1 million, it stops. My cluster health keeps fluctuating from GREEN to NOT CONNECTED in every 5-10 seconds, sometimes it is not connected for a long period of time. And this causes my re-indexing process fail completely. What are my options? How do I make my cluster health GREEN or strong all the time. I have 3 nodes, 1 master node. I am reindexing to the same cluster. From kibana, at the beginning it says time-out error, but in the background it starts re-indexing and stops little after 1 million. I have also tried re-indexing through command prompt using curl command, same issue.