Hi @Rob,I found my rrd build scripts... OK I stole them back from maccas sdcard as I had really lost them :D You really need to read the rrdtools website info to understand what the following means. Although in a nut shell it creates an empty file structure which allows you to store up to 10 variables called pnt_1 - pnt_10 and can hold consolidated data history as per the comments below.
Here is also a small script which allows you to retrieve history from the rrdfile. this can be used for testing before making trends etc. Gives an idea on how to use the rrdtool fetch commandCode:#!/bin/sh # Update interval is 5 min (300 seconds) # ROWS x SAMPLE x STEP # 10000 x 1 x (300) = 35 days (5 min steps) # 15000 x 6 x (300) = 312 days (30 min steps) # 20000 x 12 x (300) = 2.2 years (1 hr steps) # 20000 x 24 x (300) = 4.5 years (2 hr steps) # 20000 x 48 x (300) = 9 years (4 hr steps) rrdtool create /var/www/rrd/Marine.rrd --step 300 \ DS:pnt_1:GAUGE:600:-10:1000 \ DS:pnt_2:GAUGE:600:-10:1000 \ DS:pnt_3:GAUGE:600:-10:1000 \ DS:pnt_4:GAUGE:600:-10:1000 \ DS:pnt_5:GAUGE:600:-10:1000 \ DS:pnt_6:GAUGE:600:-10:1000 \ DS:pnt_7:GAUGE:600:-10:1000 \ DS:pnt_8:GAUGE:600:-10:10000 \ DS:pnt_9:GAUGE:600:-10:10000 \ DS:pnt_10:GAUGE:600:-10:10000 \ RRA:AVERAGE:0.5:1:10000 \ RRA:MAX:0.5:1:10000 \ RRA:MIN:0.5:1:10000 \ RRA:AVERAGE:0.5:6:15000 \ RRA:MIN:0.5:6:15000 \ RRA:MAX:0.5:6:15000 \ RRA:AVERAGE:0.5:12:20000 \ RRA:MIN:0.5:12:20000 \ RRA:MAX:0.5:12:20000 \ RRA:AVERAGE:0.5:24:20000 \ RRA:MIN:0.5:24:20000 \ RRA:MAX:0.5:24:20000 \ RRA:AVERAGE:0.5:48:20000 \ RRA:MIN:0.5:48:20000 \ RRA:MAX:0.5:48:20000 \
Code:!#/bin/bash rrdtool fetch /var/www/rrd/Marine.rrd AVERAGE --start end-8h --end now
Thanks for the info rrdtool create !