Marklogic - Handling documents while removing a node from cluster

Question

I have a MarkLogic cluster with 10 nodes. Each has a forest associated with it. If I am planning to retire a node from the cluster, how do I handle the documents in that node? Does MarkLogic automatically move the documents to the other nodes when it "leaves" the cluster or should I be doing a re-balancing before retiring the node?

Answer 1

If you try to leave the cluster without moving any data, you will notice it won't let you. See also the Admin guide and the Scalability, Availability, and Failover Guide. Basically, you need to:

• retire all forests assigned to the host you want to remove from the cluster
• make sure rebalance moves all files to the other nodes (this normally starts automatically after you retire a forest)
• once all files have been moved off the host (may take a while), detach all relevant forests from their databases
• delete all forests on that host
• and only then the host can leave the cluster

Additional steps might be required if replication and/or failover is involved. You will probably need to redistribute replica forests and failover hosts.

HTH!