In my opinion there are four main techniques that are used in
forecasting: analytical modeling, simulation modeling, trending and headroom
charts.
Let’s take a look at each of these:
Analytical Modeling
•
The ability to predict environment changes based upon
the arrival of work
· CPU
· IO
•
Based upon
· Baseline
timeframe (seasonal peaks and troughs, highest transaction times etc)
· Calibration of
model – Does it match real life?
· What-If
changes to model
•
Spend virtual $’s, helping you to determine what is
the best cost benefit that you can get out of it
•
Low cost modeling technique, as you’re able to take
the data and apply it going forward without making costly mistakes.
The graph below illustrates how this can be considered, always taking in
to account how the ‘end user’ will be affected.
Simulation
Modeling
There are many organizations such as Wall Street companies, who feel the
need to run simulation models but it does take longer to set up and can be very
costly.
•
Replication of environment
•
Has to stay close to production environment
•
Usage of tools to replicate workload into simulated
environment
•
Longer lead time to setup
•
Provides granular detail on environment changes
•
Can be costly
Trending
With trending you are usually looking at one metric for each chart, this
doesn’t prohibit you from having several charts looking at different metrics
for the same scenario.
•
Provide prediction based upon an interval of time
•
Quick to produce
•
Usually looking at one metric
•
Can show steps in growth changes
•
Confidence is based on length of interval and amount
of historical data
The more data that you have to feed in to your trend chart then the more
confidence you can have in the end result.
On Wednesday I'll be taking a more in-depth look at Trend types.
Charles Johnson
Principal Consultant
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