Hi there,

Im learning perl and rrdtool now. I try to make
rrdtool to monitoring cpu loadavg. Everythings seems
working (rrd db created, updated, rrd images created,
updated. i check with doing a ls -l and compare the
timestamp on those files).

However, the is only one problem that screw the whole
things -- the graph is blank wiht no line

I tried many times but still not able to get it solve.
Thus, im posting my script here and hope someone can
help me.

# cat rrd_cpu.pl
#!/usr/bin/perl
use RRDs;
my $rrd = '/var/www/htdocs/rrd_db';
my $img = '/var/www/htdocs/rrd_images';
if (! -e "$rrd/cpu.rrd") {
RRDs::create "$rrd/cpu.rrd",
"-s 300",
"DS:1min:GAUGE:600:U:U",
"DS:5min:GAUGE:600:U:U",
"DS:15min:GAUGE:600:U:U",
"RRA:AVERAGE:0.5:1:576",
"RRA:AVERAGE:0.5:6:672",
"RRA:AVERAGE:0.5:24:732",
"RRA:AVERAGE:0.5:144:1460";
}
my $min1 = `cat /proc/loadavg | cut -d" " -f1`;
my $min5 = `cat /proc/loadavg | cut -d" " -f2`;
my $min15 = `cat /proc/loadavg | cut -d" " -f3`;

RRDs::update "$rrd/cpu.rrd",
"-t", "1min:5min:15min",
"N:$min1:$min5:$min15";

RRDs::graph "$img/cpu-day.png",
"--lazy",
"-s -1day",
"-t CPU information :: day",
"-h", "120", "-w", "600",
"-a", "PNG",
"-v Load AVG %",
"DEF:imin1=$rrd/cpu.rrd:1min:AVERAGE",
"DEF:imin5=$rrd/cpu.rrd:5min:AVERAGE",
"DEF:imin15=$rrd/cpu.rrd:15min:AVERAGE",
"LINE2:imin1#ff0000:1min",
"LINE2:imin5#009f32:5min",
"LINE2:imin15#0000ff:15min";

if ($ERROR = RRDs::error) { print "$0: unable
to generate cpu graph: $ERROR\n"; }
}

Thanks in advance.

Apparently, just need to remove the eol character from the source. This is how i do it,
$line = qx/uptime/;
# to chop the trailing newline
chomp $line;