Here, you've seen that a CPU subsystem has only one run queue and why an IO subsystem without a massive cache will immediately queue transactions. I've shown you how to confirm an IO bottleneck using multiple techniques and how to maximize either response time or throughput by controlling the workload.

There are many Oracle DBAs, and there are many operating system administrators, but there are not nearly enough people who can effectively operate in both arenas. My hope is this chapter has given you the tools, strategies, and courage to begin operating in this realm.

1 CPU cores are sometimes called servers because each core serves transactions. This can be very confusing to DBAs without a predictive analysis background. DBAs typically consider each box, node, or database server to be a server. In the predictive analysis arena, it is common to speak of anything that serves transactions as a server. It could be a CPU, a CPU core, a physical IO device, an IO volume, or the server at a restaurant. If it can serve, than it's a server. However, in this book, I will try not to use the word server to avoid confusion