DBA提出的需求：
每隔一天给它们绘一张交换机总出口的流量。
测试了下RRD模块，发现功能不错，这里为大家提供一个我写的例子，供大家学习参考吧。
#!/usr/bin/perl -w
use strict;
use RRDs;
my $error;
my $starttime=`date -j -v -1d "+%s"`; #在这里可以改成date -j -v -30M "+%s"(即每隔30分钟获取一张图片)
chomp($starttime);
my $endtime=`date -j "+%s"`;
chomp($endtime);
my $path="/usr/local/share/cacti/rrdimg/";
my($averages,$xsize,$ysize )=RRDs::graph('/usr/local/share/cacti/rrdimg/tel01.png',
'--imgformat','PNG',
'-s', $starttime,
'-e',$endtime,
'--title','GZ-CSO-Tel1 - Traffic',
'--rigid',
'--base','1000',
'--height','120',
'--width','500',
'--alt-autoscale-max',
'--lower-limit','0',
'--vertical-label','bits per second',
'DEF:in=/usr/local/share/cacti/rrdimg/xxx_xxx_xxx_xxx_traffic_in_72.rrd:traffic_in:AVERAGE',
'DEF:out=/usr/local/share/cacti/rrdimg/xxx_xxx_xxx_xxx_traffic_in_72.rrd:traffic_out:AVERAGE',
'CDEF:cdefin=in,8,*',
'CDEF:cdefout=out,8,*',
'AREA:cdefin#00CF00:Inbound',
'GPRINT:cdefin:LAST: Current:%8.2lf %s',
'GPRINT:cdefin:AVERAGE:Average:%8.2lf %s',
'GPRINT:cdefin:MAX:Maximum:%8.2lf %sn',
'LINE1:cdefout#002A97:Outbound',
'GPRINT:cdefout:LAST:Current:%8.2lf %s',
'GPRINT:cdefout:AVERAGE:Average:%8.2lf %s',
'GPRINT:cdefout:MAX:Maximum:%8.2lf %sn'
);
if ( $error = RRDs::error ) {
print "rrdtool fetch failed: "$error"n";
exit 1;
}
配置crontab，在指定的时间运行，例如：
59 23 * * * /usr/bin/perl /usr/local/share/cacti/rrdimg/rrdimg.pl > /dev/null 2>&1
以上代码，每天晚上23点59分绘一张满意的图出来，是不是很酷啊。