Today at 3am Australian Eastern Daylight Time (AEDT), all my Australian servers kicked over to the Australian Eastern Standard Time (AEST) timezone.
I had a 2am cron job running on one of these servers. The result of having a cron job that is triggered at 2am on a server which sits in a timezone that supports Daylight Saving is that the cron job is ran twice when the timezone comes out of Daylight Saving.
When the server comes back into the Daylight Saving timezone the cron job would not of ran at all.
Luckily for me, this cron job isnt business critical and the fact that it ran twice had no serious impact to the operations of the business.
Lesson I learnt today. Do not schedule cron jobs at 2am.
image by pedromourapinheiro
