Safe cron minutes

06 07 08 09 11 12 13 17
18 19 21 22 23 24 26 27
33 34 36 37 38 39 41 42
43 47 48 49 51 52 53 54

Theory

Everyone runs their scheduled jobs at simple minute steps like 60, 30, 15, or 5.

   0 * * * *
*/30 * * * *
*/15 * * * *
*/ 5 * * * *

Problem

Cron aligns minutes to the clock, leading to huge spikes of usage at those intervals, as the hourly jobs, half-hourly jobs, etc, all run at once.

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Solution

Use random, unusual minutes to distribute the load. Exclude the most common minutes, and nearby minutes based on prevalence.

7 * * * *
26 */2 * * *
34,53 * * * *

Rules

Begin with the set of all minutes in the hour.

1. Exclude 5 minute intervals.
2. Exclude 15 minute intervals and nearest 1 minutes.
3. Exclude 30 minute intervals and nearest 2 minutes.
4. Exclude 60 minute intervals and nearest 4 minutes.
5. Select minutes randomly from the remaining set.

1.	2.	3.	4.	5.

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	01
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05
				06 <
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15
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	46
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50
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55
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	59
00

Conclusion

Is this really problem? Probably not; better solutions have likely taken care of it.

Don’t take 19 * * * *, though. I’m using it.