What takes the most CPU? System or User? most of it is used by
org.apache.cassandra.util.coalesceInternal and SepWorker.run Did you try
removing a problematic node and installing a brand new one (instead of
re-adding)? I did not install a new node, but did remove the problematic node
and CPU load in all the cluster became normal again When you decommissioned
these nodes, did the high CPU "move" to other nodes (probably data model/query
issues) or was it completely gone? (server issues) it was completely gone
