We had an event this morning were a node reached its high watermark. Elasticsearch decided to move 21 of its shards.
We didn't modify cluster.routing.allocation.cluster_concurrent_rebalance, so it should limit the reallocation to two, right? Is this parameter not respected when reallocations are due to a high watermark?
We had cluster.routing.allocation.node_concurrent_recoveries set to a somewhat high value (20) though, but our understanding is that this specific parameter only happen when recovering, while the move we saw were clearly labelled as a reallocation...