[rrd-users] Fetch the time of the first entry

Simon Hobson linux at thehobsons.co.uk
Wed Jul 2 08:52:38 CEST 2014


Steve Shipway <s.shipway at auckland.ac.nz> wrote:

> You seem to be misunderstanding how RRDTool works.
> 
> Remember that, after every update of an RRA, the oldest value is thrown away to make room for the new one.  So, the 'first' time (the timestamp of the oldest bucket in the RRA) will increase every time you update, as the last bucket is thrown away.
> 
> Also, the 'first' value is the oldest bucket, *whether or not it has been filled*.

As I pointed out, it looks like the documentation is a little misleading on this. Where teh database has been filled and old data thrown away then the documentation is correct - but in the OPs case, it's misleading by talking about the "first data sample entered" into the RRA.



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