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System configured to read RTC time in the local time zone

asked 2018-10-12 21:29:33 -0500

ladlelord gravatar image

When I run timedatectl, I get the following message:

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'.

What is the significance of this, and should I run timedatectl set-local-rtc 0?

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If you are not dual booting set rtc to UTC and forget about it.

fcomida gravatar imagefcomida ( 2018-10-12 22:48:53 -0500 )edit

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answered 2018-10-13 12:55:57 -0500

villykruse gravatar image

The significance is that when RTC is running in local time, then it is undefined if the current time read from RTC is current winter time or summer time. When RTC is runnint in UTC time, then the time read from the RTC is independent of current time zone or current winter/summer time. This gives fewer complications.

However, if you boot Windows on your system, it expects RTC to be in local time, so that is what it should be running as. If you only run linux on your system, then RTC should be running in UTC time.

In reality, if you have a working time server also known as NTP server, then it is less important to get the right time from the RTC clock as the NTP server will fix the time early on during system boot.

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Asked: 2018-10-12 21:29:33 -0500

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Last updated: Oct 13 '18