Tandem Capacity Model (TCM) Manual

1. Open a Workload Apportionment model.
2. Find the Capacity History database. If it is not accessible, open the desired history file. The
Capacity History screen appears.
3. Analyze the historical variance of the CPU and disk demands for the sample data, ignoring
or deleting unrepresentative data samples that might have been taken when data
communications lines were inoperative or during CPU failures.
4. Select the apportionment method that yields relatively consistent CPU and disk demands across
all the representative samples.
For more information, see “Updating the Capacity History Database” (page 80).
Calculating Throughput Trending
Calculating throughput trending is the same as calculating throughput growth rate and transaction
per task growth rate. You can use the Planning Timeline model to have TCM calculate throughput
growth rate (or transaction per task growth rate) based on the existing trend in the history database.
To calculate throughput trending:
1. Open a Performance model.
2. Select Update > Timeline Trends. The Update Timeline Trend dialog box appears.
3. Select the desired transaction to trend from the Transaction list.
4. If desired, modify the range of dates in the history database by entering new dates in the
From and To fields. The default is the entire history database. Those dates appear in the fields.
5. Click OK.
6. Select Options > Calculate Now (F9).
The transaction trend in the historical database is used to update the Planning Timeline screen.
If you are using a color monitor, the trend appears in red.
For more information, see “Throughput Trending” (page 92).
Calibrating Batch Response Time
If you observe the actual response time of batch transactions that you run on your system and want
TCM to adjust its predicted response time accordingly, you can use the Calibrate Batch Response
Time command.
To calibrate batch response time:
1. Open a Performance model.
2. Select Update > Calibrate Batch Response Time. The Calibrate Batch Response Time dialog
box appears.
3. Select the batch transaction name to calibrate from the list.
4. Type the observed response time in the Calibrate Batch Response Time dialog box or accept
the default values. You can enter hours, minutes, and seconds.
5. Make sure the Uncalibrate Transaction check box is not checked.
6. Click OK.
TCM adjusts its estimated response times in the Performance model by factors that reflect observed
response times.
For more information, see “Calibrating Batch Response Time” (page 104).
Changing Authorization Levels
Only users with a TCM administrator or superuser authorization level can create or modify the
apportionment tables (and therefore create a model).
To change authorization levels:
1. Open a model.
2. To change the authorization level either:
232 Common TCM Procedures