[CentOS] Boot time in wtmp is not correct [FIXED]

Wed Oct 13 07:44:37 UTC 2021
Hooton, Gerard <g.hooton at ucc.ie>

Not a dual boot.


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.

[EXTERNAL] This email was sent from outside of UCC.

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.
College Road.
Loc8: WDR-04-60G
Tel: +353 21 4902296
Mobile: +353 852813491