Don't start jobs between the times when clocks change in your location.
For example In the UK the clocks go forward 1 hour at 1am on the last Sunday in March, and back 1 hour at 2am on the last Sunday in October so. Therefore it is only 01:nn
times that can happen twice or not at all due to DST changes. So you can change the start time to 00:55 or 02:05 to completely avoid the 01:nn
hour so you don't get this issue (and document why you have made the change so someone doesn't change it back).
I don't like the idea of ignoring a whole hour of my maintenance window in order to defend myself from a problem that only happens once a year.
Moving from 01:05 to 00:55 is a 10 minute difference and once the job starts it will continue running during the clock change. Another alternative is to run the job at 01:05 except on the days when there is a clock change and use a different start time on those days. - MT0