lograte rotating logs at 4:02am. why not at 12:00am?

Steve Buehler steve at ibapp.com
Sat Apr 24 16:55:25 UTC 2004


At 02:16 PM 4/23/2004, Javier Gostling wrote:
>On Fri, Apr 23, 2004 at 12:03:16PM -0700, Chris W. Parker wrote:
> > my question is: why are they not starting at 12am and how can i adjust
> > this?
>
>The reason is quite simply Daylight Saving Time. If you rotate at midnight,
>as someone where I work decided before I came in, you face the following
>issues when time changes:
>
>1. When skipping from 00:00 to 01:00, if cron doesn't wake before the clock
>shift, the log rotation will not occur.
>
>2. When skipping back from 00:00 to 23:00, if cron wakes before the clock
>shift, the log will be rotated twice.
>
>I have seen both issues happen. To avoid both problems, rotate after 01:00
>and before 23:00.

Just curious on where you live?  What country do you live in?  How have you 
seen this happen?  If you are in the US, it NEVER changes at midnight.  It 
changes at 2am.  So 2am to 1am in the fall and 2am to 3am in the 
spring.  That means skipping all jobs between 2am and 3am.  At least I have 
read somewhere that the system keeps a record so that if a job goes off at 
1:30am and the time gets set back at 2am, it won't run again.  I am not 
sure of this and have not seen any official documentation on it.  I would 
try to avoid anything between 1am and 3am just to make sure unless you find 
an official answer for it.

Steve





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