详细介绍可参考http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=864861&page=1&authorid=20054105大作，介绍的很详细
我主要是想弄明白ganglia轮询来的数据怎么使用的rrdtool
如下是ganglia3.7.2-gemtad.conf中的默认配置
#Round-Robin Archives
# You can specify custom Round-Robin archives here (defaults are listed below)
#
# Old Default RRA: Keep 1 hour of metrics at 15 second resolution. 1 day at 6 minute
# RRAs "RRA:AVERAGE:0.5:1:244" "RRA:AVERAGE:0.5:24:244" "RRA:AVERAGE:0.5:168:244" "RRA:AVERAGE:0.5:672:244" \
# "RRA:AVERAGE:0.5:5760:374"
# New Default RRA
# Keep 5856 data points at 15 second resolution assuming 15 second (default) polling. That‘s 1 day
# Two weeks of data points at 1 minute resolution (average)
#RRAs "RRA:AVERAGE:0.5:1:5856" "RRA:AVERAGE:0.5:4:20160" "RRA:AVERAGE:0.5:40:52704"
原文：http://www.cnblogs.com/roger888/p/5587522.html