I have en elasticsearch cluster consisting 3 nodes, and a pretty big index (~1500 fields), and when it restarts, ether from a "clean" restart or forced shotdown, it takes a while to go back up, and it hoggs the JVM heap and indexing slow down, as described in feeds such as:
My question is not how to handle this issues, but to understand: What does elasticsearch tries to do when the cluser is restrating? what is happening behind the scenes that cause this slowdown and heavy memory usage?
To what configurations does it relate to?
I need to be able to explain the process to my peers and then think how to make the cluser restart not stop other process in the machine that also uses JVM heap memory.