Pathmaker Programming Guide

Designing a Pathmaker Application
Preparing for Pathmaker Application Development
2–8 067868 Tandem Computers Incorporated
2. Estimate service time for each service.
You can estimate the time required to perform a service by examining the number
of file I/O operations it executes. Many I/O operations result in longer run time
for a service. Estimating the service time should be sufficient for your first
configuration. If more accuracy is required, you can use Measure to time the
services. Measure is a Tandem software subsystem for collecting and examining
system performance statistics. Refer the Measure User’s Guide for detailed
information.
3. Group services by service time.
Within the groupings formed by a file set, create more groups by service time. For
example, you could create four groupings: one for fast services, one for slow
services, one for moderate services, and one for services with variable service time.
You can include services of unknown service time in the variable group.
4. Package services into servers.
The most effective packaging of services into servers depends on the total number
of services you have, their size, and the number of files they access. If you have
fewer than 40 services and few files, you can package them all into one server and
create four server classes, one for each category of service time. If you have more
than 40 services, if your services are very large, or if you have many files, you need
to create two or more servers.
5. Create server classes.
You should create one server class for each category of service time. The total
number of server classes varies depending on the number of servers you have and
the number of categories you create when you group services by service time.
6. Designate an active server class for each service.
All services could be packaged into a single server. If you have created four server
classes from that server, all services are in all four server classes. Each server class
should be dedicated to one service time grouping. In this example, there should
be one server class for fast services, one for slow services, one for moderate
services, and one for services that have a variable service time.