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InfluxDB
Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
And if you live outside reception distance of JJY or WWVB or DCF77 there's a raspberry pi local transmitter model and it runs off ntp.
Using it to sync my citizen watch in Australia.
https://github.com/hzeller/txtempus
NOTE:
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