I removed one node from the cluster, and it was fast. Now the second node removal is taking a lot of time; why?
When you remove 2 paired leaf nodes, the first one is removed quickly as it is essentially only failing over to its online pair.
However, the second leaf node, one that no longer has a pair, will need to transfer all its data to the remaining leaf nodes in the cluster. Depending on the cluster size and SingleStore version, this change of leaf state could take hours and will impact the cluster status. It will copy all the existing partitions to the other nodes, and once it is confirmed that all the data has been copied, it will then remove the leaf node.