Essential performance forecasting, part 2: I/O  Craig's Corner
Insights on Oracle technologies and trends by Craig Shallahamer
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view more of Craig's work, visit www.orapub.com.  As I wrote in
the first part of this series, forecasting Oracle performance is
absolutely essential for every DBA to understand and perform.
When performance begins to degrade, it's the DBA who hears about
it, and it's the DBA who's supposed to fix it. Fortunately, low
precision forecasting can be done very quickly and it is a great
way to get started forecasting Oracle performance. This time,
I'll focus on I/O performance forecasting.  The key metrics we
want to forecast are utilization, queue time, and response time.
With only these three metrics, as a DBA you can perform all
sorts of low precision what-if scenarios. To derive the values,
you essentially need 3 things:    • a few simple formulas   •
some basic operating system statistics   • some basic Oracle
statistics  M