NetBatch-Plus Reference Manual

Setting Up the Processing Environment
NetBatch-Plus Reference Manual—522461-002
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3. Plan Classes and Executors
To further enhance the effectiveness of CPUs as resource managers, have classes
catering for jobs with similar processing times. For example, plan classes for long jobs
and classes for short jobs.
You can also use classes to group jobs that have a common function or purpose. For
example, you could plan a class for all your organization’s payroll jobs, another for all
high-priority jobs, and one for all jobs originating from a particular department. Using
classes to group jobs in this way, however, can result in a class whose jobs have vastly
different CPU-resource requirements and processing times. Jobs from such a class
make CPU load balancing difficult. For this reason, use a class to group jobs by
function or purpose only after you establish what effect jobs from that class have on
CPU-management activities.
NetBatch-Plus does not limit the number of classes you can set up for each scheduler.
As the number of classes increases, however, so does the complexity of managing
those classes.
To determine a practical limit for class numbers, multiply the number of executors in a
scheduler by eight (the maximum number of classes you can assign to an executor).
For example, a scheduler with four executors could have 32 classes (8 classes x 4
executors).
As with scheduler names, consider class naming conventions. Because you can use
wild-card characters on some screens to specify multiple classes, give classes names
you can mask easily with those characters.
Executors
The information you use to plan a scheduler’s classes also helps you plan the
executors for that scheduler. Executors perform a similar function to classes
(controlling CPU workload).
The number of executors you plan depends on how many CPUs are in your system
and on the CPU and I/O resource requirements of your jobs. The recommended
number of executors for each CPU is four:
•
One executor for classes whose jobs are grouped by function or purpose (for
example, an executor for jobs in a class used by a particular department).
•
One executor for classes whose jobs are CPU-bound.
•
Two executors for classes whose jobs are I/O-bound. You can have more than two
executors for these classes; this depends on the power of your CPUs and the
number of logical devices configured for each CPU. For example, a NonStop
Cyclone system with eight disks per CPU can handle more executors than a
NonStop CLX system with two disks per CPU.
Before you assign executors to those CPUs, consider existing loads on CPUs. For
example, a CPU might be running a critical online Pathway application. Increasing that
CPU’s workload by directing batch jobs to it via executors might affect the application’s