To minimize complexity and maximize scalability metrics are aggregated and time-aligned on the source.
It uses the nagios service_perfdata_file_processing_command on a 30sec interval (0.02s real/wall time usage).
flush 1m-avg CpuIdle - 1433451960 - 1433452020
time:val:delta:weight 1433451992:96.39:32:0.53
time:val:delta:weight 1433452052:96.18:28:0.47
aggregate: 96.292
…
<epoc> <pretty time> <ci_id>:<ci_name>:<bucket-stat (1m-avg)> <perf blob (key=value space delimited)>