The OS Load: Average column displays the average amount of processes using or waiting for CPU on your node over a period of time.
Average OS load larger than the number of cores indicates that the CPU was temporarily overloaded and reached the limits of its processing capacity. If you are experiencing consistently high OS load and not reaching the desired throughput on your Cassandra cluster, you may need to tune your data model or add nodes to your cluster to increase processing capacity. Contact firstname.lastname@example.org if you need further assistance in dealing with OS load issues.
Under the OS Load group, the OS Load: Average graphs displays the average amount of work the computer system performs on each node.