problem:
i had someone who setup cacti. now i want to change from cacti to librenms.
installing went fine and i added some of the equipment (core 1+2 and distribution 1+2)
the admin who set up cacti said that librenms doesn’t show the graphics properly. There are differences.
for example - Distribution 1 - Ethernet port 1/1 - last 6 hours:
librenms:
the distribution as equpiment was put by the admin. He said that there must be a bug by librenms that there are those differences.
i don’t now where to look… could be that the RRD-file are messed up? but then i ask myself how can it be… both servers are on snmp v2 and both should get the same informations.
if someone can tell me where to look so i can find where the differences are, would be great.
When you don’t index spikes in graph it’s the bit’s, then may be the poller and after that rrd’s Why does not your admin try to search for the problem ?
reinstalled librenms. left it untouched for a period of time (just added devices). RRD step was too high so i tuned it down to 100 and heartbeat to 200 (network blocked snmp because rrd step was too high). Polling otherwise is ok and works perfectly fine. all equipment go with snmp v2.
Graph are almost the same. still, i’m not really where i want it to be. Can it be that librenms is cutting spikes automatically? still wouldn’t explain the differences between the graphs if i zoom it in. why is it inacurate?
between 20:10 and 20:15 i have in cacti 100mbps and in librenms only 50mbps
between 19:50 and 19:55 the graph doesn’t look at all the same. the values are also completely different.
almost the same. a little bit past 18:00 i’m missing the spike where in cacti in goes to 100mbps and in librenms only 20mbps. at 16:45 (behind the 300mbps bar) there should be the graph value higher and not on the average red line.
it’s not very accurate. @murrant can you help me make librenms more accurate in graph?
(btw. this problem is for every device. not only this one)
poller in distribution should be around 15sec. so polling is fine i guess.
Think about this. If you transfer 750 Megabytes in one minute, but 0 bytes the other 4 minutes of that 5 minute interval what is the transfer rate for the 1 minute interval and the 5 minute interval? 100Mbps and 20Mbps.
LibreNMS is accurate, but you are measuring rate over a period of time with different periods of time You are not measuring the peak transfer rate during the time period, but the average (in both Cacti and LibreNMS)
So to compare apples to apples. Add all 5 1 minute intervals from Cacti, then divide by 5.
Also you are assuming that we ask for the data at the same time as cacti which is most likely not the case, therefore you can expect the device to give us different data back, especially if traffic is bursty.
@laf@murrant that wouldn’t be the problem. if it’s close as possible then i’m ok. i changed cron poller-wrapper from 5 to 1 and rrd to 60 and heartbeat to 120 sec. i’ll see tomorrow how the graph will change.
my goal is that the graph is as close to reality as possible. i don’t want that librenms is equally to cacti. but i hope that it’s close so i won’t get fooled if something happens.
furthermore i want to build on it and give it to clients so they can monitor their servers. but i need to know that graphing works properly and is as close to reality as it gets. if the graphing is 30-60 mbps short, then that’s a problem because that’s not reliable. (example some client goes rogue and makes constantly more traffic than contractual defined. i need to proof. if he does 150mbps but libre shows only 100mbps then i can’t make him pay for the extra traffic)
that’s what and why i’m struggling here. it may not be your concern but still saying so you understand my situation.
Why does not your admin try to search for the problem ?
