Famille Michon, le 20/05/2014 à 15:55
Construction de courbes de prévision (forecast) à partir d'une base RRD + calcul de l'atteinte de la date d'atteinte d'une valeur donnée.

Utiliser la méthode des moindres carrés (Least Square Line) qui permet d'obtenir une ligne d'équation y=ax+b.
La fonction LSLOPE fournit a, LSLINT fournit b.
Voir aussi LSLCORREL qui fournit la qualité de l'approximation : "LSLCORREL is the Correlation Coefficient (also know as Pearson's Product Moment Correlation Coefficient). It will range from 0 to +/-1 and represents the quality of fit for the approximation."
(voir ici : http://oss.oetiker.ch/rrdtool/doc/rrdgraph_rpn.en.html)


"""
#! /usr/bin/perl
use RRDs;

$rrd_file = 'MEMORY.rrd';

RRDs::graph "MEMORY_Trend.png",
'--start', "10/24/2009",
'--end', "12/31/2009 00:00am",
'--title', "Memory Usage",
'--interlace', '--width=620', '--height=200',
"--color","ARROW#009900",
'--vertical-label', "Memory used (%)",
'--lower-limit', '0',
'--upper-limit', '100',
'--border','0',
'--rigid',

"DEF:used1=$rrd_file:used:AVERAGE",
"DEF:used2=$rrd_file:used:AVERAGE:start=10/24/2009",
"DEF:used3=$rrd_file:used:AVERAGE:start=-1w",
"DEF:used4=$rrd_file:used:AVERAGE:start=-2w",
"DEF:used5=$rrd_file:used:AVERAGE:start=-4w",
"DEF:free1=$rrd_file:free:AVERAGE",
"DEF:free2=$rrd_file:free:AVERAGE:start=10/24/2009",
"DEF:free3=$rrd_file:free:AVERAGE:start=-1w",
"DEF:free4=$rrd_file:free:AVERAGE:start=-2w",
"DEF:free5=$rrd_file:free:AVERAGE:start=-4w",

"CDEF:pused1=used1,100,*,used1,free1,+,/",
"CDEF:pused2=used2,100,*,used2,free2,+,/",
"CDEF:pused3=used3,100,*,used3,free3,+,/",
"CDEF:pused4=used4,100,*,used4,free4,+,/",
"CDEF:pused5=used5,100,*,used5,free5,+,/",

“LINE1:90″,
“AREA:5#FF000022::STACK”,
“AREA:5#FF000044::STACK”,

"COMMENT:                         Now          Min             Avg             Max\\n",
"AREA:pused1#00880077:Memory Used",
'GPRINT:pused1:LAST:%12.0lf%s',
'GPRINT:pused1:MIN:%10.0lf%s',
'GPRINT:pused1:AVERAGE:%13.0lf%s',
'GPRINT:pused1:MAX:%13.0lf%s' . "\\n",
"COMMENT: \\n",

'VDEF:D2=pused2,LSLSLOPE',
'VDEF:H2=pused2,LSLINT',
'CDEF:avg2=pused2,POP,D2,COUNT,*,H2,+',
'CDEF:abc2=avg2,90,100,LIMIT',
'VDEF:minabc2=abc2,FIRST',
'VDEF:maxabc2=abc2,LAST',

'VDEF:D3=pused3,LSLSLOPE',
'VDEF:H3=pused3,LSLINT',
'CDEF:avg3=pused3,POP,D3,COUNT,*,H3,+',
'CDEF:abc3=avg3,90,100,LIMIT',
'VDEF:minabc3=abc3,FIRST',
'VDEF:maxabc3=abc3,LAST',

"AREA:abc2#FFBB0077",
"AREA:abc3#0077FF77",
"LINE2:abc2#FFBB00",
"LINE2:abc3#0077FF",

"LINE1:avg2#FFBB00:Trend since 24 Oct 2009                      :dashes=10",
"LINE1:avg3#0077FF:Trend since 1 week\\n:dashes=10",
"GPRINT:minabc2:  Reach  90% @ %c :strftime",
"GPRINT:minabc3:  Reach  90% @ %c \\n:strftime",
"GPRINT:maxabc2:  Reach 100% @ %c :strftime",
"GPRINT:maxabc3:  Reach 100% @ %c \\n:strftime",

;

my $ERR=RRDs::error;
die "ERROR : $ERR" if $ERR;
"""
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