# RRD file creation # # A COUNTER value is stored as a derivative with physical dimension "per second" # according to RRDtool documentation # # The step size is dt = 60s. (This is the wanted resolution of the measurement.) # # A power distribution box can have a maximum power throughput of # Pmax = 3 x Imax x 400V # # We have Imax = 63A for normal distribution boxes and Imax = 250A for the main # distribution # # The impulse constant is imp = 1000/kWh for most distribution boxes, # imp = 800/kWh for some old ones and imp = 10000 for the main distribution # board. # # The maximum number of impulses between two measurements is # Nmax = imp * Pmax * dt # # The maximum derivate is # dNmax = Nmax/dt = imp * Pmax # # This results into # # (a) for most distribution boxes # dNmax = 1000/kWh * 75600W = 756/36 1/s = 21/s # # (b) for some old distribution boxes # dNmax = 800/kWh * 75600W = 84/5 1/s = 16.8/s # # (c) for the main distribution box # dNmax = 10000/kWh * 300kW = 10000/12 1/s = 833.3/s # # # The primary step size is 1min. We keep 525600 records. This is 1 year. # The next step size is 15min. We keep 70080 records. This are 2 years. # The coarsest step size is 60min. We keep 43800 records. This are 5 years. # # The command to create the database is: /usr/bin/rrdtool create \ /srv/cacti/rra/power.rrd \ --step 60 \ DS:01:COUNTER:120:0:18 \ DS:02:COUNTER:120:0:18 \ DS:06:COUNTER:120:0:18 \ DS:07:COUNTER:120:0:22 \ DS:10:COUNTER:120:0:850 \ DS:11:COUNTER:120:0:18 \ DS:12:COUNTER:120:0:22 \ DS:16:COUNTER:120:0:22 \ DS:17:COUNTER:120:0:22 \ DS:21:COUNTER:120:0:22 \ DS:22:COUNTER:120:0:22 \ DS:26:COUNTER:120:0:22 \ DS:27:COUNTER:120:0:22 \ DS:31:COUNTER:120:0:22 \ DS:32:COUNTER:120:0:22 \ DS:36:COUNTER:120:0:22 \ DS:37:COUNTER:120:0:22 \ DS:41:COUNTER:120:0:22 \ DS:46:COUNTER:120:0:22 \ DS:47:COUNTER:120:0:22 \ RRA:AVERAGE:0.5:1:525600 \ RRA:AVERAGE:0.5:15:70080 \ RRA:AVERAGE:0.5:60:43800 \ RRA:MIN:0.5:1:525600 \ RRA:MIN:0.5:15:70080 \ RRA:MIN:0.5:60:43800 \ RRA:MAX:0.5:1:525600 \ RRA:MAX:0.5:15:70080 \ RRA:MAX:0.5:60:43800 \ RRA:LAST:0.5:1:525600 \ RRA:LAST:0.5:15:70080 \ RRA:LAST:0.5:60:43800 \