http://wiki.lustre.org/Check_MK/Graphite/Graphios_Setup_Guide
Dell PowerEdge R515
2x 8-Core AMD Opteron 4386
300GB RAID1 15K SAS
200GB Enterprise SSD
64GB RAM
~150k checks per minute
~200k metrics per minute
每台服务器用于存储rrd的空间平均100M
300G / 100M = 3000台主机
