How Calendar Scheduling Interacts with Daily Windows

Daily windows are taken into account, even when calendar-based scheduling is used. Windows that span midnight, effectively become two separate windows for calendar scheduling. For the first backup after the policy is created, this can sometimes appear as though two backups have run within the same window.

If the calendar schedule indicates that today is a run day, the backup will run once during any window that is open. For example:

1. A new backup policy is created on Monday afternoon. The windows are configured to be open from 6 p.m. until 6 a.m., Sunday through Saturday.
2. In the Calendar Schedule tab, the schedule is set up to run on recurring week days, Monday through Saturday.
3. Since this is a new policy, no backup yet exists based on this policy. And since today (Monday) is a run day, a job will run as soon as the window opens at 6 p.m.
4. At midnight, it is a new day (Tuesday) and there is a window open (until 6 a.m.) so the job is due and will run again. The backups will continue to run soon after midnight from that time forward.

Notice how it is possible for the backup to run just before midnight, then again immediately after midnight. This is valid since both are different run days and windows are open at both times (6 a.m. through 6 p.m. every day of the week). Windows that span midnight, effectively become two separate windows for calendar scheduling.

If the desired result is to run jobs at 6 p.m. instead of midnight, use a frequency of one day instead of setting up recurring days in the Calendar Schedule tab.