The Growth Rate Report provides the values of the long- and short-term compound growth rates for the variables that you specify on the Profile and Trending Analysis control screen (see Figure 5-6). Figure 5-2 shows a sample Growth Rate Report.
+----------------------------------------------------------------------------------------------------------------------------------+ |SYSID: TSO1| | | | EXTENDED EXAMPLE --- GROWTH RATE PER MONTH | |ZONE: 1 | | |-----------+----------------------------------------------------------------------------------------------------------------------| | | CHANNEL 1 | CHANNEL 2 | CHANNEL 3 | CHANNEL 4 | CHANNEL 5 | | | | INTERVAL | BUSY (%) | BUSY (%) | BUSY (%) | BUSY (%) | BUSY (%) | | | |-----------+----------------+----------------+----------------+----------------+----------------+----------------+----------------+ | 11 MOS | 4.40 % | 4.57 % | -2.02 % | 3.63 % | -0.24 % | | | | LAST MO | 23.94 % | 47.08 % | -19.22 % | -8.37 % | -13.52 % | | | +----------------------------------------------------------------------------------------------------------------------------------+
Figure 5-2. Growth Rate Report
The following information is shown:
SYSID: The SYSID specified by the SYSID control
parameter.
ZONE: The ZONE specified by the LVL control
parameter.
INTERVAL: Two interval values are shown in the report.
The first interval identifies the number of
intervals used to compute the long-term rate of
growth. The second interval specifies either
LAST WK, LAST MO, or LAST DY depending on the
time-span you specified for the Capacity
Planning database file.
You can specify the remaining columns of the report using
the control parameters on the Profile and Trending Analysis
control screen. For example, the first column of the report
shown in Figure 5-2 contains the following information:
CHANNEL 1 The two rates of growth that are shown for
BUSY (%): channel 1 utilization. The long-term growth
rate (that is, for the last 11 months) for
utilization is 4.40%. Simply stated, the
August 1998 value of 8.6% busy represents a
4.40% compound increase per month from the
value recorded for September 1997. The short-
term rate of growth (that is, 23.94%) is the
percent difference between the values for July
and August 1998.
These growth rates provide a sense of direction for the
variables you specify. In general, the long-term growth rate
is a much more reliable estimator, since it is less
susceptible to step function changes that occur when a new
workload is introduced. The short-term growth rate value is
useful for determining when a long-term trend has been
reversed.
For example, the channel utilization values for channel 4
(see Figure 5-2) were growing at a long-term rate of growth
of 3.63%. However, the differences between July and August
1998 result in a short-term rate of growth of -8.37%. The
sign difference between the long- and short-term rates
represents a trend reversal.
A positive long-term growth rate does not imply that each of
the observations in the historical series has been steadily
increasing, but only that the long-term trend between the
first and last observation is positive (see Figure 5-1 for
channel 1).
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