Subj : tzdata question
To   : ACCESSION
From : Dumas Walker
Date : Wed Apr 02 2025 09:19:00

>  DW> /etc/localtime -> pointed as shortcut to correct timezone
>  DW> /etc/timezone -> contained the correct timezone

> This might depend on if you're using systemd or not. In my case (Archlinux), I
> have '/etc/localtime' which is symlinked to the correct timezone in
> '/usr/share/zoneinfo'. I don't have '/etc/timezone', and I use ntpd to keep my
> time synced.

/etc/localtime is symlinked to the correct timezone until a tzdata update
is received, then it resets it to "Indianapolis."

> Seeing as how you're using Debian and Devuan (one can only assume here that on
> has systemd and the other does not, since you didn't specify), you may want to
> check to see if 'ntpd' is installed and running properly:

Correct re: systemd and not.  ;)

>  DW> This is happening on every debian/devuan/raspbian system that I have,
>  DW> and it started happening sometime during the past month or six weeks
>  DW> after I received a kernel/tzdata update.

> Does tzdata actually do anything, though? Pretty sure it simply just provides
> the time zone information needed for all other applications or runtimes in the
> operating system to print local time correctly. I can't imagine tzdata is to
> blame, here.. unless the Debian maintainers completely jacked that package up,
> and for Debian variants only.

At the very least, tzdata resets /etc/localtime and /etc/timezone, which the
system and other applications use to determine the local timezone and
therefore correct time vs. GMT.  So it does do "something."  ;)

> When you type 'sudo hwclock' what do you see? Is it displaying the correct
> timezone offset? And does it match your results for the 'date' command?

Yes, it is correct right now.  Not sure if it would be if I were to let
tzdata run again.

>  DW> I thought the time zone was saved in the two above places in /etc.  Is
>  DW> there some other place that tzdata is reading from that I need to look
>  DW> at so that, in future, whenever tzdata gets updated I don't have to
>  DW> remember to go back and manually fix the time zone each time?

> Those are probably the two most common places, but might vary slightly between
> distros. I think tzdata is what is read (by other applications), and doesn't d
> any reading of anything on it's own (but I could be wrong). I can't imagine
> this is tzdata's fault, though, or it would be all over the Linux interwebz
> since it's a pretty important package, and not just specific to you.

I don't think it is "tzdata's fault," per se, but it very obviously on my
systems has "Indianapolis" saved *somewhere* other than the two places I
would know to look.... /etc/timezone and /etc/localtime... and I need to
find it and quash it.  ;)

I have checked in /etc, /var, and a couple of other places for a config
file but don't see one.  Someone else suggested running grep on the
contents of /etc and looking for "Indianapolis."  I will try that if I can
figure out how to get grep to run on a whole directory?

> If you don't have some kind of application or service setup to sync and retain
> your time and timezone information, I recommend using one.

Will ntpd use the hwclock time to determine this, or does it rely on
/etc/localtime?  If it uses the latter, I suspect it will be wrong, too. ;)


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