Input/output blockages in the Cassandra cluster
Address input/output (I/O) blockages in a Cassandra cluster or low CPU resources by reviewing the CPU statistics.
From a Linux terminal, run the top command.The Linux terminal returns a report on system resource usage and current processes.
In the Linux report, find the CPU usage section (%Cpu(s)).The CPU usage section shows the percentage of CPU time spent on various tasks, for example:
%Cpu(s): 12.8 us, 2.3 sy, 0.0 ni, 84.4 id, 0.3 wa, 0.0 hi, 0.2 si, 0.0 st
The value of the wa parameter reflects the time that the CPU spends waiting for I/O operations to complete.
If the value of the wa parameter is higher than 1, investigate the source of the problem, for example, by performing other Cassandra troubleshooting procedures.For more information, see the Troubleshooting section of the Apache Cassandra documentation.