Daylight Saving Time and backups problem

Question

Daylight Saving Time and backups problem

A programmed backup of databases on one of my servers occurs at 6:00 am every morning. This is configured using Lingon (interface to Launchd)
Afterwards, using Bombich's Carbon Copy Cloner, this backup is transferred to a remote machine.

Today, October 31, Daylight Saving Time went in effect and surprisingly two backups occurred one at 5 am and the other at 6 am.
I am looking for some ideas or explanations of such behavior.

Thanks

MacBook Pro Core 2 Duo, MacBook Core 2 Duo, PowerBook G4, iMac G4, iMac G3, Mac OS X (10.6.4), 2.33 GHz 3 GB RAM disk 160 MB, iPhone 3G 4.0.2

Posted on Oct 31, 2010 1:32 AM

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Answer 1

Klaus1

Level 9

52,873 points

Oct 31, 2010 1:57 AM in response to eddy kestemont

When your clock reset itself to winter time it arrived at 6 am a second time and triggered a backup.

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Answer 2

Oct 31, 2010 5:56 AM in response to eddy kestemont

hi not the perfect answer but setting your alarm an hour earlier helps ie set 05.30 for it to go off 6.30

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Answer 3

Oct 31, 2010 6:55 AM in response to Klaus1

Not sure this explains what happened. Daylight saving time change is at 3 am resetting the clock to 2 am.
And in any case, it is only one time 6 am even on this particular day.

The problem must lie deep into Launchd mechanism I think

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