Although the RRD is being given a COUNTER, what it is storing is the Rate. It has already done most of your work for you!
Therefore, your fetch command is returning the average Rate (in octets per second) for that 30s time window. Multiple by 8 and you'll have it in bits/sec Steve Steve Shipway [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Munroe Sollog Sent: Tuesday, 8 April 2014 3:08 p.m. To: rrd-users Subject: [rrd-users] Pulling data out of rrds I have thousands of rrds that store network traffic data. My goal is to get the 'current bandwidth usage' from each. I'm taking the the last 2 entries from: rrdtool fetch switch_hud/data/datab/172.16.23.250-g0-1.rrd MAX --resolution 30 I'm subtracting the values and multiplying by 8 because I'm collecting octets. My understanding is that because the rrds are collecting a counter from the switches subtracting the n-1 value from the nth value gets me the total # of bits over the given time. If I divide that by the time span I should get bits per second. However, my numbers are 2-3 orders of magnitude off when I compare it to the graph and I can't figure out why. My hope is that there is an easier way to do what I'm trying to do. The graph seems to be able to do this trivially. Included is the output from rrdtool info $ rrdtool info switch_hud/data/datab/172.16.41.251-g1-0-1.rrd filename = "switch_hud/data/datab/172.16.41.251-g1-0-1.rrd" rrd_version = "0003" step = 30 last_update = 1396925867 header_size = 2048 ds[inbps].index = 0 ds[inbps].type = "COUNTER" ds[inbps].minimal_heartbeat = 120 ds[inbps].min = 0.0000000000e+00 ds[inbps].max = NaN ds[inbps].last_ds = "8910377490" ds[inbps].value = 5.3340333333e+03 ds[inbps].unknown_sec = 0 ds[outbps].index = 1 ds[outbps].type = "COUNTER" ds[outbps].minimal_heartbeat = 120 ds[outbps].min = 0.0000000000e+00 ds[outbps].max = NaN ds[outbps].last_ds = "35576830451" ds[outbps].value = 1.2401500000e+04 ds[outbps].unknown_sec = 0 rra[0].cf = "MAX" rra[0].rows = 5760 rra[0].cur_row = 1089 rra[0].pdp_per_row = 1 rra[0].xff = 5.0000000000e-01 rra[0].cdp_prep[0].value = NaN rra[0].cdp_prep[0].unknown_datapoints = 0 rra[0].cdp_prep[1].value = NaN rra[0].cdp_prep[1].unknown_datapoints = 0 rra[1].cf = "MAX" rra[1].rows = 2880 rra[1].cur_row = 2 rra[1].pdp_per_row = 12 rra[1].xff = 5.0000000000e-01 rra[1].cdp_prep[0].value = 2.9445444444e+02 rra[1].cdp_prep[0].unknown_datapoints = 0 rra[1].cdp_prep[1].value = 8.3342888889e+02 rra[1].cdp_prep[1].unknown_datapoints = 0 rra[2].cf = "MAX" rra[2].rows = 1440 rra[2].cur_row = 217 rra[2].pdp_per_row = 48 rra[2].xff = 5.0000000000e-01 rra[2].cdp_prep[0].value = 3.2185555556e+02 rra[2].cdp_prep[0].unknown_datapoints = 0 rra[2].cdp_prep[1].value = 1.1610480460e+03 rra[2].cdp_prep[1].unknown_datapoints = 0 rra[3].cf = "MAX" rra[3].rows = 2920 rra[3].cur_row = 2147 rra[3].pdp_per_row = 288 rra[3].xff = 5.0000000000e-01 rra[3].cdp_prep[0].value = 3.8953555556e+02 rra[3].cdp_prep[0].unknown_datapoints = 0 rra[3].cdp_prep[1].value = 1.1610480460e+03 rra[3].cdp_prep[1].unknown_datapoints = 0 rra[4].cf = "MAX" rra[4].rows = 1040 rra[4].cur_row = 207 rra[4].pdp_per_row = 2016 rra[4].xff = 5.0000000000e-01 rra[4].cdp_prep[0].value = 5.4072455556e+03 rra[4].cdp_prep[0].unknown_datapoints = 0 rra[4].cdp_prep[1].value = 4.7447486667e+04 rra[4].cdp_prep[1].unknown_datapoints = 0 _______________________________________________ rrd-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
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