Tandem Capacity Model (TCM) Manual

disk volumes, their configuration type, their write cache (WCE) configuration status and TMF
audit trail count. Valid disk write cache configuration status can be:
WCE enabled for disks that support WCEEnabled
WCE disabled for disks that support WCEDisabled
NA for disks that do not support WCENA
For audited disk configurations, valid TMF audit trails can be between 1 and 16. For unaudited
configurations, it is NA (not applicable). The WA model assigns an Aud disk configuration
type if there are any audited transactions. If none are audited and the number of logical and
physical disks are equal, it assigns an Unmirr disk type. Otherwise, the WA model assigns
an Unaud disk type.
2. Fixed Read Sec—Not directly modifiable
Fixed Read Sec is the total number of CPU seconds consumed per second by process categories
of type F (fixed). This number is not included in the CPU and disk consumption of individual
transactions but does affect the total CPU and disk utilizations. Define a category as type F if
its CPU and disk consumption do not increase as throughput increases, such as during
asynchronous data communications polling activity or the running of Measure.
3. Apportionment—Not directly modifiable
Apportionment indicates the apportionment method used by the WA screen. The apportionment
method name is the name of the apportionment table file (without the .AWA extension) that
was used to generate the apportionment formulas when Workload Apportionment was selected
from the Update menu.
Significant Columns
4. Txn Name—Modifiable by the TCM administrator
Txn Name is the name of the transaction as defined on the NonStop host system using
MeasTCM. In MeasTCM, you can specify the transaction names for each transaction in the
application or applications being modeled. You can specify up to 40 transactions.
If no transaction names are specified in MeasTCM, TCM assumes that each server category
(type S) represents a transaction and uses the corresponding server category names as
transaction names.
5. First Unlabeled Column—Not directly modifiable
The first unlabeled column shows the type of a transaction, either X for OLTP transactions, B
for batch transactions, or Q for query transaction.
6. Second Unlabeled Column—Not directly modifiable
The second unlabeled column indicates Aud if the transaction is audited but is left blank
otherwise. A transaction is considered audited if it has a nonzero entry in the TMF process
category in the Apportionment Weights table.
7. # Tasks—Modifiable by the TCM administrator
# Tasks is the number of tasks on the NonStop host system during the time period of the sample
window. This number applies to batch transactions only.
8. # Txns—Not directly modifiable
# Txns is the number of transactions on the NonStop host system during the time period of the
sample window. This number is computed according to the user-specified Transaction Count
table, which specifies how to calculate the number of transactions from the number of messages
received, sent or both by the process categories, or is input through the Transaction Count
Disk Read Workload Apportionment Screen 111