Time adjustments and scheduling jobs

Daylight savings time adjustments

When daylight savings time (DST) begins (“spring forward”), the local time jumps from 0200 to 0300. The Job Scheduler “catches up” by running all jobs scheduled between 0200 and 0300 the next time it wakes up. This prevents jobs from being skipped when they appear in the 0200 to 0300 time frame.

When daylight savings time (DST) ends (“fall back”), the local time jumps from 0200 to 0100. The Job Scheduler skips all jobs scheduled between 0100 and 0200 to allow local time to catch up. Those jobs already ran once before DST ended will not repeat.


If an administrator configures a new job during the repeat of the 0100 to 0200 hour on the day DST ends, the new job will not be run because the Job Scheduler skips that hour.

External adjustments

External adjustments to the system time can happen to correct for clock drift or for other administrative reasons. The new time update can come from SNTP, from a configuration command at the CLI, or from an SNMP SET of the system time MIB object. When a time adjustment takes place, the Job Scheduler task is called with the new clock value. Jobs scheduled during a time clock jump forward are run while any jobs scheduled during a time clock jump back are skipped.

Adjustment of more than 10 minutes are considered a major change and reset the Job Scheduler. Any jobs scheduled during a time clock jump forward are skipped while any jobs scheduled during a time clock jump back are repeated.

Calendar conflicts

Because the Job Scheduler MIB is more flexible than the CLI scheduling grammar, it is possible to create job schedules via SNMP that cannot be displayed by the CLI. The following rules are imposed on MIB values to limit them to what the CLI can display.

  • If any bits are set in hpicfJobSchedulerEvent, all Calendar values are ignored. They may be set with SNMP, but are ignored when looking for jobs to run. The Calendar values are also ignored by the command show running-config.

  • If any bit is set in CalendarDayOfWeek, then CalendarMonth and CalendarDayOfMonth are ignored.

  • If no bits are set in CalendarDayOfWeek or CalendarDayOfMonth, then CalendarMonth is ignored.

  • Only 1 bit may be set in the CalendarMonth, CalendarDayOfMonth, CalendarHour, and CalendarMinute objects. Attempting to set a value with more than 1 bit returns an InconsistentValue error.

  • If no bits are set in CalendarHour and CalendarMinute, the job is considered to be in a transition state and not valid. This could happen when an SNMP management application is creating a job one object at a time. Jobs in this state are ignored by the scheduler and by the command show running-config.