Availability Guide for Change Management

Reducing the Time Required for Planned Outages
Availability Guide for Change Management–125506
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Product-Specific Techniques
Example 2: Starting a Transaction-Processing Application in a
PATHMON Environment
You can reduce the time required to start a transaction-processing application in a
PATHMON environment by using multiple startup command files in different
processors. To implement this technique, you must divide your PATHMON
configuration into convenient and related units. An example of a unit would be a
terminal control process (TCP) and its terminals.
Once you have divided your PATHMON configuration into units, you can divide the
entire startup process into multiple startup files, one for each unit. Processing can then
be distributed among the available processors in your system.
The number of discrete startup units is not constrained by the number of processors—
you can run multiple startup processes concurrently in the same processor by invoking a
TACL process with the NOWAIT option to execute the command file. However, the
PATHWAY MAXPATHCOMS attribute must be set to accommodate the maximum
number of PATHCOM processes that can run simultaneously within a PATHMON
environment.
When using this technique, make sure that you consider other processes or applications
that may be using the system at the same time as the transaction-processing application.
For example, if the transaction-processing application is started from a completely
quiesced system, full parallel processing can be implemented. However, if the
application is started while other user processes or applications are active, processor
utilization of parallel processing may cause degradation of response time.
Product-Specific Techniques
The startup and shutdown techniques described in this subsection do not represent all the
possible ways you can reduce startup and shutdown time. Certain products provide
commands, options, or techniques that can help you reduce the time required to start up
and shut down your applications.
For example, NonStop TS/MP provides the cool start option and the SHUTDOWN2
command to reduce startup and shutdown, respectively. You should use the cool start
option rather than the cold start option to restart an existing transaction-processing
system, because it is usually much faster. The SHUTDOWN2 command provides a
faster, more reliable shutdown operation than the SHUTDOWN command. Both of
these techniques—and guidelines for when you should use them—are described in the
NonStop TS/MP System Management Manual.
For information about startup and shutdown techniques for a particular product, refer to
the operations and management manual for that product.