[SOLVED] Graph of disk and net from influxdb/grafana

mbaldini

Active Member
Nov 7, 2015
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Hello.

Following the guide at https://pve.proxmox.com/wiki/External_Metric_Server I configured my proxmox servers to send status data to an influxdb server, it's working and I can see nodes measurements and VM/LXC measurements, graphing them in grafana with influxdb data source. But I can't understand what is the format of fields diskread/diskwrite/netin/netout from the table system.

I can make a graph with memory stats (fields: maxmem/mem), cpu stats (fields: cpu) but for disk and net activity I cannot understand in what format are the values that proxmox send.

See an example of graphs for a Windows 2012 VM:
OJfmjLc.png
As you can see in the two graphs in the bottom row, I am receiving the right values, in fact memory and cpu graphs are working right.
In the graphs in the top row I used the fields netin, netout, diskread, diskwrite but those values have no sense to me, always growing while I think I should have activity values (bytes/sec)

This is an example of the query I used for those graphs:
cV8vBO1.png

If you can tell me how to analyze the values in those fields, it could be very useful to me.

Thanks
 

dcsapak

Proxmox Staff Member
Staff member
Feb 1, 2016
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they are in bytes written/read/sent/received

if you want a graph for a rate you have to add a transformation -> non negative derivative
 

mbaldini

Active Member
Nov 7, 2015
170
21
38
Thanks for your reply.

I just added the transformation as you said and now the graph is working as it should, the last problem is that values I see in the Grafana graph are different from the values I see in the Proxmox GUI in the same time range.

Look at examples:

This is the graph of disk usage from Proxmox GUI, at time 15:03 diskwrite is 9.67 MB/s
5mp0bOY.png

This is in Grafana, at time 15:03 diskwrite is 13.08 MB/s and it's not the graph peak as it is in the Proxmox GUI
iff5TbF.png

In the graph peak as seen in Grafana, I get a value of 286.9 MB/s, this value seems too high to me, in fact in Proxmox GUI I don't have such a value
oYVqQea.png

I suppose I'm still having some mistake in the query, but I can't understand what, I am not practical with the non_negative_derivative transformation so I don't know how to use that well.

Thanks
 

dcsapak

Proxmox Staff Member
Staff member
Feb 1, 2016
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you have different timespans

since the source data is absolute and cumulative, there are no values for single points in time, but only for a timespan. in the gui the smallest timespan you can get is 1 minute, in your grafana example you have 10s

so if i write with 100 mbyte/s for 1 second and then 59 second nothing, the value for a 10 second interval will be 10mbyte/s for the first 10s and 0 for the rest
if my interval is 60 seconds, my value will be 1.6666 mbyte/s
 

mbaldini

Active Member
Nov 7, 2015
170
21
38
Ok, thanks.

The interval of 60 seconds is ok for me, so I'll change the timespan in the graphs.
Thank you very much
 

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