Linux – How precise is a cron daemon

cronlinux

Is the cron job scheduler really precise?

I mean, I need a script to run every night the latest possible, BUT before 00:00 of the next day.

I'd ideally run a cron job at 23.59 (or 11:59 pm), but will the system be really precise? Since a second does matter, should I set the cron job to 23:58 to leave it some time?

Best Answer

What cron can guarantee is that your job will start no sooner than the specified time (subject to precision of the system clock). But there is no way to give you any guarantee about the termination time of the job. It will depend on a lot of factors:

  • How loaded is the system
  • What does the job do
  • Slowness due to hardware issues
  • Slowness due to networking issues (assuming the job depends on networking)

My recommendation is to change your design such that a specific completion time is not a requirement.

Related Topic