Linux – Slowdown the system clock in Linux server

clocklinuxlinux-kernel

I have Centos server, in which I don't want to jump back the time to one hour during time change. instead I want to slow down the system clock few hour before the time change so that when the time jumps back, my server should sync with latest time after time change

Best Answer

As said in the comments, switching on DST won't change your machine time at all, only the timezone. Therefore you don't need to mess with the server clock (and you're advised not to).

On a side note, there's a project that does something similar to what you want. Google uses it to "smear" the extra second over a longer time whenever the IERS enforces a leap second. Basically, during a whole day, Google server clocks run a bit slower so that when the leap second is applied at midnight the servers experience no time jump. Again, I add this just FYI -- this is not a solution for your case.

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Linux – Automatically synchronization between system time and hardware clock time

You could write a function that does both:

set_both_clocks() {
  date "$@"
  hwclock -w
}

Give it the exact same arguments you'd give to date when setting the system clock.

RTC and System clock not in sync

You can use the hwclock command to set the hardware clock.
From the man hwclock page :

 --set  Set the Hardware Clock to the time given by the --date option.

You can apply the current system time to the hw clock with :

hwclock -w

or even manually with :

hwclock --set --date "$(date)"

After you added details to your question, my answer is not enough though, so here are more details below.
You can check timezone with the timedatectl status command.
List timezones with timedatectl list-timezones.
You can set your timezone to UTC for example with timedatectl set-timezone UTC.
You will find more details about timezone settings here.

Best Answer

Related Solutions

Linux – Automatically synchronization between system time and hardware clock time

RTC and System clock not in sync

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