Cron vs anacron: which scheduler for laptops and servers that don't run 24/7?

How this is calculated

Anacron schedules are defined in days, not minutes. You can say 'run this job daily' or 'run this weekly' but not 'run at 2:15 AM.' When anacron starts, each due job waits for its configured delay and then runs independently of other jobs by default. The -s option serializes jobs, while -n starts due jobs immediately and also implies serial execution. On a server that runs 24/7, cron is better because it gives you precise wall-clock timing. On a laptop that sleeps overnight, anacron ensures the daily backup runs after the machine becomes available again. Modern Linux distributions typically run both: cron handles minute-level precision for always-on jobs, and anacron catches up daily, weekly, and monthly maintenance tasks.

Verdict

The dividing line is whether the machine stays on. Anacron works in day units only, with no minute or hour fields. Due jobs run independently after their own delay by default, and become sequential only with -s or -n. A laptop that sleeps overnight misses the cron slot entirely, but anacron catches the daily backup after the machine becomes available again. Mainstream distros run both, so minute-level cron and day-level anacron maintenance cover the full range.