This article may come in handy. For some reason, I’ve had a number of requests over the past week about iowait on Linux.

The big problem is that people don’t seem to understand the relationship between iowait and load. They see a very high load and very few processes and they can’t figure out why the load is so high.

When running ‘top’, look to the iowait percent number. If it’s high, the CPU is spinning its tires waiting on io. The referenced article can tell you how to find the culprit. You then need to figure out how to smooth out the bottleneck. If it’s temporary, you may have to just ride it out. If it’s a permanent process, such as MySQL, you may have to redesign your disk.