CentOS - Oct 2021 - Boot time in wtmp is not correct [FIXED]

> On 12.10.2021, at 17:41, Hooton, Gerard <g.hooton at ucc.ie> wrote:
> 
> When I do who -b; uptime I get
> 
> system boot  2021-10-12 17:05
> 16:36:09 up 30 min,  1 user,  load average: 0.00, 0.00, 0.00
> 
> As you can see the boot time reported by the last command is ahead.
> I have noted it is  one hour ahead after a reboot.
> 
> I have checked the system time in the BIOS  before booting Linux and it is
correct.
What do you mean with ?correct?? UTC or localtime?

For me timedatectl gives me

```
$ timedatectl
?
RTC in local TZ: no
?
```

Which means that RTC/BIOS clock is in UTC, so when booting the timezone offset
is added. I heard that dual boot with Windows makes 
problems because Windows is setting RTC always with local time. In
that case try "RTC in local TZ: yes"

Do you dualboot? What is timedatectl telling you?

Best Regards, Markus

Not a dual boot.

timedatectl

Local time: Wed 2021-10-13 08:37:56 IST
           Universal time: Wed 2021-10-13 07:37:56 UTC
                 RTC time: Wed 2021-10-13 08:37:56
                Time zone: Europe/Dublin (IST, +0100)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: yes

Warning: The system is configured to read the RTC time in the local time zone.
         This mode cannot be fully supported. It will create various problems
         with time zone changes and daylight saving time adjustments. The RTC
         time is never updated, it relies on external facilities to maintain it.
         If at all possible, use RTC in UTC by calling
         'timedatectl set-local-rtc 0'.

I use the command 'timedatectl set-local-rtc 0' as suggested above and
that fixed the problem.

-----Original Message-----
From: Markus Falb <wnefal at gmail.com<mailto:Markus%20Falb%20%3cwnefal at
gmail.com%3e>>
Reply-To: CentOS mailing list <centos at
centos.org<mailto:CentOS%20mailing%20list%20%3ccentos at
centos.org%3e>>
To: CentOS mailing list <centos at
centos.org<mailto:CentOS%20mailing%20list%20%3ccentos at
centos.org%3e>>
Subject: Re: [CentOS] Boot time in wtmp is not correct
Date: Wed, 13 Oct 2021 00:36:13 +0200
Mailer: Apple Mail (2.3608.120.23.2.7)


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On 12.10.2021, at 17:41, Hooton, Gerard <

<mailto:g.hooton at ucc.ie>

g.hooton at ucc.ie
> wrote:

When I do who -b; uptime I get


system boot  2021-10-12 17:05

16:36:09 up 30 min,  1 user,  load average: 0.00, 0.00, 0.00


As you can see the boot time reported by the last command is ahead.

I have noted it is  one hour ahead after a reboot.


I have checked the system time in the BIOS  before booting Linux and it is
correct.


What do you mean with ?correct?? UTC or localtime?


For me timedatectl gives me


```

$ timedatectl

?

RTC in local TZ: no

?

```


Which means that RTC/BIOS clock is in UTC, so when booting the timezone offset

is added. I heard that dual boot with Windows makes

problems because Windows is setting RTC always with local time. In

that case try "RTC in local TZ: yes"


Do you dualboot? What is timedatectl telling you?


Best Regards, Markus

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--

Gerard Hooton.
Senior Technical Officer
School of Engineering.
University College Cork.
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Ireland.
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