AS 2.1 did not execute cron job on 2:10 A.M. SUNDAy ???

[Ed Greshko]

On Tue, 2004-04-06 at 01:47, Ed Wilts wrote:
> On Mon, Apr 05, 2004 at 05:10:12PM +0000, bbaa aaa wrote:
> > Thanks.  But I don't think it is bug on SUN, the reason is SUN and HP-UX 
> > both work correctly on 2:30 A.M.
> 
> So both Solaris and HP-UX are broken.  There is no 2:30 AM, so what time
> did the cron jobs actually run?  At 3am (the first increment past 2am),
> 3:30 am (half-hour after 2am), or 1:30am (half-hour before 3am)? 

Sorry to burst you bubble....

>From the man page of HP/UX cron....

Notes
      On the days of daylight savings (summer) time transition (in time
      zones and countries where daylight savings time applies), cron
      schedules commands differently than normal.

      In the following description, an ambiguous time refers to an hour and
      minute that occurs twice in the same day because of a daylight savings
      time transition (usually on a day during the Autumn season).  A non-
      existent time refers to an hour and minute that does not occur because
      of a daylight savings time transition (usually on a day during the
      Spring season).  DST-shift refers to the offset that is applied to
      standard time to result in daylight savings time.  This is normally
      one hour, but can be any combination of hours and minutes up to 23
      hours and 59 minutes (see tztab(4)).

      When a command is specified to run at an ambiguous time, the command
      is executed only once at the first occurrence of the ambiguous time.

      When a command is specified to run a non-existent time, the command is
      executed after the specified time by an amount of time equal to the
      DST-shift. When such an adjustment would conflict with another time
      specified to run the command, the command is run only once rather than
      running the command twice at the same time.

      For commands that are scheduled to run during all hours by specifying
      a * in the hour field of the crontab entry, the command is scheduled
      without any adjustment.


So, HP/UX (as well as Solaris) are not "broken".  They are designed to work that way.
Kind of like getting up in the middle of the night to take a leak.  Just because you
"normally" do it at 2AM doesn't mean you skip it when DST happens.  :-)

Regards,
Ed

> They could not have possibly run at 2:30AM when you told them to since
> there was no 2:30AM.
> 
>         .../Ed
>  
> > >From: Ed Wilts <ewilts at ewilts.org>
> > >To: General Red Hat Linux discussion list <redhat-list at redhat.com>
> > >Subject: Re: AS 2.1 did not execute cron job on 2:10 A.M. SUNDAy ???
> > >Date: Mon, 5 Apr 2004 09:52:10 -0500
> > >
> > >On Mon, Apr 05, 2004 at 01:12:05PM +0000, bbaa aaa wrote:
> > >> I know day light saving time reset on 2:00 A.M., but SUN server cron job
> > >> (2:10 A.M.) work correctly without problem.
> > >
> > >Then that would be a bug on the SUN servers.  2:10AM didn't exist and I
> > >contend that your AS servers did the right thing.
> > >
> > >        .../Ed
> > >
> > >> >From: "Tom" <duffer at usa.net>
> > >> >To: "General Red Hat Linux discussion list" <redhat-list at redhat.com>
> > >> >Subject: RE: AS 2.1 did not execute cron job on 2:10 A.M. SUNDAy ???
> > >> >Date: Mon, 5 Apr 2004 08:09:00 -0500
> > >> >
> > >> >I belive, that the official time to change to daylight savings is 2 A.M 
> > >so
> > >> >if your system reset the time at 2 A.M, then there was no 2:30 for the 
> > >cron
> > >> >job to run.  Assuming you went to dailight savings time at 2:00 am.
> > >> >
> > >> >
> > >> >-----Original Message-----
> > >> >From: redhat-list-bounces at redhat.com
> > >> >[mailto:redhat-list-bounces at redhat.com]On Behalf Of bbaa aaa
> > >> >Sent: Monday, April 05, 2004 7:33 AM
> > >> >To: redhat-list at redhat.com
> > >> >Subject: AS 2.1 did not execute cron job on 2:10 A.M. SUNDAy ???
> > >> >
> > >> >
> > >> >We have Redhat AS 2.1 e-38.  On Sunday all the servers did change time, 
> > >but
> > >> >cron job on 2:30 A.M. did not execute.
> > >> >
> > >> >It happen on all servers.
> > >> >
> > >> >does anyone know why?
> 
> -- 
> Ed Wilts, Mounds View, MN, USA
> mailto:ewilts at ewilts.org
> Member #1, Red Hat Community Ambassador Program
-- 
"An opinion is like an asshole - everybody has one."
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