[gentoo-user] Problems after DST change

[gentoo-user] Problems after DST change

[Mark Knecht]

Hi all,
   One of my machines had problems with the early DST changes. I guess
I hadn't updated something. The machine is our Myth backend server so
it doesn't get as many updates as my desktop machines which had no
problems.

   Yesterday I *think* I fixed it but I'm wondering what I Can do to
test that it's *really* fixed without rebooting it. How can I test
that NTP is working from the command line or with some small app?

Thanks,
Mark
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Re: [gentoo-user] Problems after DST change

[Albert Hopkins]

On Mon, 2007-03-12 at 06:44 -0700, Mark Knecht wrote:
> Hi all,
>    One of my machines had problems with the early DST changes. I guess
> I hadn't updated something. The machine is our Myth backend server so
> it doesn't get as many updates as my desktop machines which had no
> problems.
> 
>    Yesterday I *think* I fixed it but I'm wondering what I Can do to
> test that it's *really* fixed without rebooting it. How can I test
> that NTP is working from the command line or with some small app?
> 

Well, are you talking about NTP or your timezone data (NTP knows nothing
about timezones and vice versa).  The timezone data is in the
timezone-data package (not surprisingly).  My understanding is that if
you live in the United States and have any version released after 2005
you should be okay, but you can always see what your time zone data
looks like with the zdump(8) command.

--
Albert W. Hopkins

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Re: [gentoo-user] Problems after DST change

[Mark Knecht]

On 3/12/07, Albert Hopkins <marduk@gentoo.org> wrote:
> On Mon, 2007-03-12 at 06:44 -0700, Mark Knecht wrote:
> > Hi all,
> >    One of my machines had problems with the early DST changes. I guess
> > I hadn't updated something. The machine is our Myth backend server so
> > it doesn't get as many updates as my desktop machines which had no
> > problems.
> >
> >    Yesterday I *think* I fixed it but I'm wondering what I Can do to
> > test that it's *really* fixed without rebooting it. How can I test
> > that NTP is working from the command line or with some small app?
> >
>
> Well, are you talking about NTP or your timezone data (NTP knows nothing
> about timezones and vice versa).  The timezone data is in the
> timezone-data package (not surprisingly).  My understanding is that if
> you live in the United States and have any version released after 2005
> you should be okay, but you can always see what your time zone data
> looks like with the zdump(8) command.
>
> --
> Albert W. Hopkins

Yes, I saw Roger's post in another thread which I copied here. I did
all that and ran zdump. It looks similar to Rogers. I'm in California:

<QUOTE>
1) Sync.

(2) emerge timezone-data (should be >= 2006p)

(3) set TIMEZONE="Canada/Newfoundland" in /etc/conf.d/clock (adjust
   for your local time zone).

(4) rm /etc/localtime && cp /usr/share/zoneinfo/Canada/Newfoundland
   /etc/localtime (adjust for your local time zone).

(5) Check: zdump -v /etc/localtime | grep 2007.
   For timezone-data = 2007c it shows:

/etc/localtime  Sun Mar 11 03:30:59 2007 UTC = Sun Mar 11 00:00:59
2007 NST isdst=0
/etc/localtime  Sun Mar 11 03:31:00 2007 UTC = Sun Mar 11 01:01:00
2007 NDT isdst=1
/etc/localtime  Sun Nov  4 02:30:59 2007 UTC = Sun Nov  4 00:00:59
2007 NDT isdst=1
/etc/localtime  Sun Nov  4 02:31:00 2007 UTC = Sat Nov  3 23:01:00
2007 NST isdst=0
<QUOTE>

And here is mine:

dragonfly ~ # zdump -v /etc/localtime | grep 2007
/etc/localtime  Sun Mar 11 09:59:59 2007 UTC = Sun Mar 11 01:59:59
2007 PST isdst=0
/etc/localtime  Sun Mar 11 10:00:00 2007 UTC = Sun Mar 11 03:00:00
2007 PDT isdst=1
/etc/localtime  Sun Nov  4 08:59:59 2007 UTC = Sun Nov  4 01:59:59
2007 PDT isdst=1
/etc/localtime  Sun Nov  4 09:00:00 2007 UTC = Sun Nov  4 01:00:00
2007 PST isdst=0
dragonfly ~ #

dragonfly ~ # date
Mon Mar 12 08:29:08 PDT 2007
dragonfly ~ #


The problem I'm having is that I don't know how to figure out if the
machine would have the correct date when I reboot.

thanks,
Mark
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Re: [gentoo-user] Problems after DST change

[Albert Hopkins]

Mark,

First, I too have a host named "dragonfly"... did you happen to root my
box? ;-)

On Mon, 2007-03-12 at 08:30 -0700, Mark Knecht wrote:
> Yes, I saw Roger's post in another thread which I copied here. I did
> all that and ran zdump. It looks similar to Rogers. I'm in California:
> 
> <QUOTE>
> 1) Sync.
> 
> (2) emerge timezone-data (should be >= 2006p)
> 
> (3) set TIMEZONE="Canada/Newfoundland" in /etc/conf.d/clock (adjust
>    for your local time zone).
> 
Not sure, if you are living in California, that you set your timezone to
Canada/Newfoundland... though admittedly, I don't know the TZ rules in
Canada.  Did they too change their DST dates?

> (4) rm /etc/localtime && cp /usr/share/zoneinfo/Canada/Newfoundland
>    /etc/localtime (adjust for your local time zone).
> 
> (5) Check: zdump -v /etc/localtime | grep 2007.
>    For timezone-data = 2007c it shows:
> 
> /etc/localtime  Sun Mar 11 03:30:59 2007 UTC = Sun Mar 11 00:00:59
> 2007 NST isdst=0
> /etc/localtime  Sun Mar 11 03:31:00 2007 UTC = Sun Mar 11 01:01:00
> 2007 NDT isdst=1
> /etc/localtime  Sun Nov  4 02:30:59 2007 UTC = Sun Nov  4 00:00:59
> 2007 NDT isdst=1
> /etc/localtime  Sun Nov  4 02:31:00 2007 UTC = Sat Nov  3 23:01:00
> 2007 NST isdst=0
> <QUOTE>
> 
> And here is mine:
> 
> dragonfly ~ # zdump -v /etc/localtime | grep 2007
> /etc/localtime  Sun Mar 11 09:59:59 2007 UTC = Sun Mar 11 01:59:59
> 2007 PST isdst=0
> /etc/localtime  Sun Mar 11 10:00:00 2007 UTC = Sun Mar 11 03:00:00
> 2007 PDT isdst=1
> /etc/localtime  Sun Nov  4 08:59:59 2007 UTC = Sun Nov  4 01:59:59
> 2007 PDT isdst=1
> /etc/localtime  Sun Nov  4 09:00:00 2007 UTC = Sun Nov  4 01:00:00
> 2007 PST isdst=0
> dragonfly ~ #
> 
> dragonfly ~ # date
> Mon Mar 12 08:29:08 PDT 2007
> dragonfly ~ #
> 
> 
> The problem I'm having is that I don't know how to figure out if the
> machine would have the correct date when I reboot.

You don't need to reboot.  Well, maybe if you made this change recently
(e.g. after DST changed) you do.  But basically what you are seeing
(from zdump) looks ok to me, meaning at 11 Mar 10:00:00 UTC your local
time is 3:00 AM and DST switches on. and on 4 Nov 9:00:00 UTC your local
time is 1:00 AM and DST switches off.
 
--
Albert W. Hopkins

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Re: [gentoo-user] Problems after DST change

[Mark Knecht]

On 3/12/07, Albert Hopkins <marduk@gentoo.org> wrote:
> Mark,
>
> First, I too have a host named "dragonfly"... did you happen to root my
> box? ;-)

No, my wife watches 'Gilmore Girls' and there is a business on that
show called the Dragonfly Inn' so she chose dragonfly. I like the name
though.

>
> On Mon, 2007-03-12 at 08:30 -0700, Mark Knecht wrote:
> > Yes, I saw Roger's post in another thread which I copied here. I did
> > all that and ran zdump. It looks similar to Rogers. I'm in California:
> >
> > <QUOTE>
> > 1) Sync.
> >
> > (2) emerge timezone-data (should be >= 2006p)
> >
> > (3) set TIMEZONE="Canada/Newfoundland" in /etc/conf.d/clock (adjust
> >    for your local time zone).
> >
> Not sure, if you are living in California, that you set your timezone to
> Canada/Newfoundland... though admittedly, I don't know the TZ rules in
> Canada.  Did they too change their DST dates?

No, I should have said that I set TIMEZONE="America/Los_Angeles" even
though I'm north in the SF Bay Area.
>
<SNIP>
> >
> > And here is mine:
> >
> > dragonfly ~ # zdump -v /etc/localtime | grep 2007
> > /etc/localtime  Sun Mar 11 09:59:59 2007 UTC = Sun Mar 11 01:59:59
> > 2007 PST isdst=0
> > /etc/localtime  Sun Mar 11 10:00:00 2007 UTC = Sun Mar 11 03:00:00
> > 2007 PDT isdst=1
> > /etc/localtime  Sun Nov  4 08:59:59 2007 UTC = Sun Nov  4 01:59:59
> > 2007 PDT isdst=1
> > /etc/localtime  Sun Nov  4 09:00:00 2007 UTC = Sun Nov  4 01:00:00
> > 2007 PST isdst=0
> > dragonfly ~ #
> >
> > dragonfly ~ # date
> > Mon Mar 12 08:29:08 PDT 2007
> > dragonfly ~ #
> >
> >
> > The problem I'm having is that I don't know how to figure out if the
> > machine would have the correct date when I reboot.
>
> You don't need to reboot.  Well, maybe if you made this change recently
> (e.g. after DST changed) you do.

I did, and I have rebooted. I *think* things are right but I'm trying
to be careful. There seem to have MythTV problems all over the place
yesterday with Zap2It labs possibly having shows at the wrong times,
etc., so it's unclear where all the problems might be.

> But basically what you are seeing
> (from zdump) looks ok to me, meaning at 11 Mar 10:00:00 UTC your local
> time is 3:00 AM and DST switches on. and on 4 Nov 9:00:00 UTC your local
> time is 1:00 AM and DST switches off.
>

Humm...........humm.......humm.......<crash>

OK, I need to go read somewhere. Actually, that part you wrote is very
clear, but isn't UTC time the same as Greenwich Mean Time? Maybe GMT
isn't effected by DST?

I normally think of California being 8 hours behind GMT. 3AM seems to
be 7 hours behind UTC and not 8 hours. Since we got DST 3 weeks early
maybe GMT didn't shift yet? Or maybe GMT never shifts?

Leave it to the American government to create world wide problems.
(Not the first time, obviously and unfortunately not the last.)

Thanks,
Mark
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Re: [gentoo-user] Problems after DST change

[Roger Mason]

Albert Hopkins <marduk@gentoo.org> writes:

> Not sure, if you are living in California, that you set your timezone to
> Canada/Newfoundland... though admittedly, I don't know the TZ rules in
> Canada.  Did they too change their DST dates?
>

Newfoundland did.  Presumably rest of Canada did so as well.

I applied the series of steps in my previous post to two boxes at home
yesterday (i.e. after the DST change took place) and both rebooted
with correct times.

Cheers,
Roger

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Re: [gentoo-user] Problems after DST change

[Albert Hopkins]

On Mon, 2007-03-12 at 09:34 -0700, Mark Knecht wrote:
> OK, I need to go read somewhere. Actually, that part you wrote is very
> clear, but isn't UTC time the same as Greenwich Mean Time? Maybe GMT
> isn't effected by DST?

Yeah... kinda.  The name "GMT" is for the most part historical.
Nowadays it's more commonly called UTC. UTC is Universal Coordinated
Time.  It is DST agnostic and doesn't change (thank your chosen deity).
> 
> I normally think of California being 8 hours behind GMT. 3AM seems to
> be 7 hours behind UTC and not 8 hours. Since we got DST 3 weeks early
> maybe GMT didn't shift yet? Or maybe GMT never shifts?

Pacific Standard Time is UTC-8 and Pacific Daylight Time is UTC-7.  UTC
(GMT if you will) doesn't change, ever.

> Leave it to the American government to create world wide problems.
> (Not the first time, obviously and unfortunately not the last.)
>  

Can't blame the Americans alone for this one.  There have been a few
countries who have changed DST rules in recent years, some even worse
than here in the U.S.

--
Albert W. Hopkins

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Re: [gentoo-user] Problems after DST change

[Mark Knecht]

On 3/12/07, Albert Hopkins <marduk@gentoo.org> wrote:
> On Mon, 2007-03-12 at 09:34 -0700, Mark Knecht wrote:
> > OK, I need to go read somewhere. Actually, that part you wrote is very
> > clear, but isn't UTC time the same as Greenwich Mean Time? Maybe GMT
> > isn't effected by DST?
>
> Yeah... kinda.  The name "GMT" is for the most part historical.
> Nowadays it's more commonly called UTC. UTC is Universal Coordinated
> Time.  It is DST agnostic and doesn't change (thank your chosen deity).
> >
> > I normally think of California being 8 hours behind GMT. 3AM seems to
> > be 7 hours behind UTC and not 8 hours. Since we got DST 3 weeks early
> > maybe GMT didn't shift yet? Or maybe GMT never shifts?
>
> Pacific Standard Time is UTC-8 and Pacific Daylight Time is UTC-7.  UTC
> (GMT if you will) doesn't change, ever.

Got it. Makes sense. Thanks!

>
> > Leave it to the American government to create world wide problems.
> > (Not the first time, obviously and unfortunately not the last.)
> >
>
> Can't blame the Americans alone for this one.  There have been a few
> countries who have changed DST rules in recent years, some even worse
> than here in the U.S.
>

Cheers,
Mark
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