[rrd-users] Getting NaN in CDEF with LIMIT but the DEF has a validnumber

Simon Hobson linux at thehobsons.co.uk
Wed Dec 28 09:47:24 CET 2011

Tom Jefferson wrote:
>Thanks for the suggestion, that is indeed the issue. So when using 
>a LIMIT in a CDEF should you allow for a little overage on your 

Any time you do any floating point calculation, you can get these 
rounding errors. And since you have to be very careful and precise in 
what you supply to RRD to avoid it normalising the data, then it's 
likely to happen with most data.

I suspect most people use limit to set loose bounds on the data to 
catch faulty inputs, rather than hard bounds like you've set.

Simon Hobson

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