[rrd-users] Why aren't COUNT and LSLSLOPE(COUNT), COUNT, *, LSLINT(COUNT), + identical?
"Peter Valdemar Mørch (Lists)"
4ux6as402 at sneakemail.com
Mon Jan 10 14:17:31 CET 2011
( I know the subject is pseudo-rpn... ;-) )
I expect that if I have one CDEF that essentially is COUNT and another
that is a linear approximation of COUNT they should be identical (since
COUNT is a line). In this reproduction recipe, I expected "count" and
"trend" to have the same values, but the generated graph shows that they
Why is that? Is it a peculiarity of COUNT or some weirdness of LSL*?
# We don't really need any data, just an rrd file.
# (taken from the first example from rrdcreate)
rrdtool create temperature.rrd --step 300 DS:temp:GAUGE:600:-273:5000
RRA:AVERAGE:0.5:1:1200 RRA:MIN:0.5:12:2400 RRA:MAX:0.5:12:2400
# Now we make a graph
rrdtool graph rrd.png --width 500 --step 648000 --height 300 --start
1288566000 --end 1295046000 DEF:temp=temperature.rrd:temp:AVERAGE
CDEF:count=temp,POP,COUNT VDEF:a=count,LSLSLOPE VDEF:b=count,LSLINT
CDEF:trend=temp,POP,a,COUNT,*,b,+ LINE1:count#FF0000 LINE1:trend#0000FF
(so "a" == 1 and "b" == 1). rrdtool xport gives similar results (but
doesn't allow me to print out "a" and "b")
Graph rrd.png can be seen in the link above:
Peter Valdemar Mørch
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