systemd-timesyncd FallbackNTP and Hardware Clock Synchronization
0 reputation · 27 Sept 2024, 03:35 UTC
Time Synchronization Configuration
In openSUSE, systemd-timesyncd manages network time synchronization by reading primary NTP servers from /etc/systemd/timesyncd.conf. While the service handles system clock updates, there is a distinction between updating the system time and the hardware clock (RTC), especially when the hardware clock is configured to use local time instead of UTC.
Hardware Clock Consistency
When the hardware clock is set to local time via hwclock --systohc --localtime, the synchronization process may result in an inconsistent state because systemd-timesyncd primarily targets the system clock. This creates uncertainty regarding how the RTC is maintained during fallback events when the primary NTP server is unreachable and the service switches to the FallbackNTP pool.
Given a systemd version 249 or newer, the following behaviors require clarification:
- Does
systemd-timesyncdtrigger a hardware clock update specifically after a successful fallback synchronization? - How does the
SyncIntervalsetting impact the latency of the fallback transition when the primary server returns an error versus being completely unreachable?
