[rrd-users] Consolidating to a Daily RRA

nhoeller at sinet.ca nhoeller at sinet.ca
Wed Mar 5 17:32:25 CET 2014

I have been using rrdtool to capture and consolidate solar radiance, 
temperature and production from a solar array.  The ability of rrdtool to 
work with large volumes of information at different granularity has been 
very useful.  Perhaps even more important has been gaining an 
understanding of the issues around data quality and the details of 

One issue has been the daily consolidation.  I understand the benefits of 
working in UTC and using midnight UTC as the daily roll-over time. 
However, it turns out that in my case roll-over occurs at 19:00 EST or 
20:00 EDT which means early evening data sometimes gets moved to the next 

I understand the challenges of using local midnight.  I have also reviewed 
some of the workarounds including using a local timestamp (this will cause 
issues if I want to create graphs) and exporting hourly data into another 
'daily' rrd (significantly larger primary rrd).  Would adding an option 
that allows us to configure an offset from UTC for the typical 'end of 
day' be useful and easily implementable?  For my purposes, I can work in 
EST and ignore Daylight Savings.
        Thanks, Norbert
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