Rob Seaman wrote: >but there are some interesting choices like 47 minutes after the hour,
I make a point of randomising the phase of all my cron jobs. Cron makes it easy to schedule a job for the same time every hour or every day, so I tend to use hourly or daily cycles but with a static random selection of phase. E.g., my job to check for a new version of the Olson timezone database runs at 7 minutes past each hour, because 7 is what came out of "echo $((RANDOM%60))" (zsh) when I set it up. Another technique I've seen is to put a random sleep first thing in the job's commands, so that it's dithered per run. >I was taken by the 17 minute cycle quoted for one of the issues >in several reports (though perhaps borrowing from the same source). >Anybody know what that was about? That's ntpd. It uses power-of-two numbers of seconds for the pauses between polls of each peer, and so tends to update tracking parameters on that cycle. (It doesn't maintain a strict cycle time; you get an approximate cycle dominated by that pause time.) It goes up to 1024 s, which is 17 min + 4 s. "ntpq -c pe" shows the selected pause time for each peer in the "poll" column. -zefram _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
