Unique to a job prototype (or more accurately, any type of batch job component), is the feature of job retention—essentially a “disposal” configuration for its previously executed jobs. When a batch job is disposed, any associated files stored on the Supervisor are deleted, and that job is removed from the various job list views.
Disposal is especially important in regards to jobs with backup steps, each of which results in an associated backup .dist file to be stored for each station. Over time, retaining all such jobs can consume an excessive amount of file space on a Supervisor.
Although a Supervisor platform typically has large amounts of hard drive storage, it is common (and recommended) for it to
be periodically backed up to removable media. Thus, it would be unwise to retain forever all daily (or even weekly) backups
for even a modestly-sized system—that would needlessly create a huge number of backup files under the station’s provisioningNiagara directory. This is where automatic disposal via job retention configuration is useful.
By default (as copied from the provisioningNiagara palette), a job prototype component’s retention is set for all of its jobs to be permanently retained (until manually disposed). However, you can (and often should) modify a job prototype’s retention policy such that some executed jobs will be automatically disposed—depending on either the “elapsed time” or by reaching some number of job executions.
Access a job’s retention properties on either the top of its Prototype Job List view (Figure 30), or in the component’s property sheet.
The two retention properties are described as follows:
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Retention Policy — This determines how long (or many) executed batch jobs are retained in the station’s job management system, after which they are disposed. Choices include:
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Retain permanently — All executed batch jobs remain in the Supervisor’s station job management system, until manually disposed.
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Dispose after a specified amount of time — Executed batch jobs are disposed after some period of time (relative to their “end” timestamp).
The field editor allows selection of a period including days, hours, and minutes (default 7 days).
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Keep a limited number of executions — Only the most recent number
nof executed batch jobs are retained, after which older jobs are disposed.The field editor provides a numerical entry field (for example, 10 executions). Included is a checkbox (flag) to specify whether only successful job executions are to be counted.
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Retention Policy Check Frequency — (1 hour for job from palette). The periodic frequency at which the job’s Retention Policy is evaluated and enforced. Note that you can also manually invoke the “Enforce Retention Policy” action on the job component. See the next Job actions section.
Keep in mind that if you configure retention properties and then duplicate/copy the job prototype, that all copied job components will have that same retention configuration.