Version 15.1 User’s Manual

Performance Management - Understanding Trend Analysis (cont)
Understanding trend analysis is key to understanding how changing environments will change
our performance and capacity requirements. First, we need a clear and concise definition of
the trend line. It is: The straight line, which best fits the data.
What Is A Trend?
A trend line can be drawn with two or more data points. That is, a starting data point and an
ending data point technically make up a trend. But obviously a trend of only two points is not
an accurate account of what is really happening on our system. As you do trending analysis,
your experience plays a big role. You’re going to know your data better than anyone else, so
you’ll know what a reliable trend is. Saying that however, you do have the ability to make the
trend any number of data points you desire. On the graph below, note the trend line on the
top of the DASD data:
This is a trend line. Notice that it stretches over many data points. (In our example,
Jan ’10 – Feb ’11)
On the next page, we will show how by right clicking on the trend line, various
trending options are available to us.
Version 15 User Manual Page 124 Oct 2011