Tandem Capacity Model (TCM) Manual

To select a worksheet either:
• Click its sheet tab at the bottom of the screen
• Use the TCM Find command to find it
The TCM Find command can find the Trend charts or Mix charts (if present) as well as the
History database.
Trend Chart
The TrendCharts worksheet has one Trend chart for each transaction name in the History data.
Each Trend chart has two plot areas, one in the top half and one in the bottom half. The top half
plots the CPU Seconds per Transaction. The bottom half plots the TPS rate (if OLTP), or the
Transactions per Task rate (if Batch), and a best-fit linear trend line. Sample dates are on the x-axis
and apply to both halves of the chart.
The Trend chart is designed so you can easily see how transaction rates change over time from
sample to sample and how the corresponding transaction cost (CPU time per transaction) varies
by sample. If a reasonable apportionment scheme was used when adding the data to the History
file, the transaction cost will not vary too much from sample to sample and should not be a function
of the sample transaction throughput rate.
The Capacity Planner can use the transaction rate trend line from the Trend chart to estimate future
expected transaction rates for samples beyond those that occur in the History file. The Performance
model already allows for automated linear trend estimation of transaction throughput rates. These
History Trend charts make it easier for you to see and work with these existing rate trends in
graphical form.
Mix Chart
The MixCharts worksheet contains one Mix chart for every sample in the History data. Each Mix
chart is a 3-D pie chart showing the percentage of CPU activity each named transaction consumed
during that data sample. This data is plotted from the Mix column of the History data.
Workload Apportionment Ribbon
The WA model tabs are listed at the top of the screen in a ribbon. To select tabs and their options,
you can either point and click with a mouse, or enter commands from the keyboard. In addition,
you can select some of the most common commands by pressing a function key.
File Tab
The File tab is used to perform common operations on Workload Apportionment files, such as
opening or closing a model.
Open (F5)
The Open option opens apportionment tables or a Capacity History database. A dialog box then
displays a list of the history databases or apportionment tables that are in the current folder.
Save (F6)
The Save option saves all the WA model files, a selected apportionment table, or a Capacity
History database.
Save As
The Save As option allows you to save all the WA model files, a selected apportionment table, or
a Capacity History database with a different file name.
Workload Apportionment Ribbon 125