[Xymon] where does xymon client get tcp packet data?

[Japheth Cleaver]

On 1/13/2016 12:38 PM, John Thurston wrote:
> On 1/13/2016 11:21 AM, John Thurston wrote:
>> The below relates to linux, xymon 4.3.17
>>
>> I was going to write a script to collect and report numbers of TCP
>> packet retransmissions. But when I look at the 'trends' for this host, I
>> see there is already a chart for "TCP/IP statistics" which includes
>> "In/Out/Retrans"  - snip -
>
> Ohhh. I think I see. It probably _is_ lining up with the numbers being 
> reported by nstat. The difficulty is the number is being graphed as 
> packets/second and plotted on the same chart as IN and OUT packets 
> (also being graphed in packets/second). My small number of 
> retransmissions is being lost in the noise of the total volume of 
> packets.

Yep. It varies by client OS, but the interface and network statistics 
are coming from the ifconfig and netstat commands, or their local 
equivalents. Those sections in the raw client message are isolated and 
turned into distinct data messages by xymond_client, which are 
interpreted and stored by xymond_rrd. It's the only two-level message 
re-injection occurring out of the box.

> Is there a way to re-define the graph to display a multiple of the 
> recorded value? Or plot this counter against an alternate y-axis set 
> to a different scale?
>
> I suppose I could define a new graph to contain only retransmissions 
> so the small number isn't swamped by the general traffic count.

This would probably be your best option. As long as it's coming out of a 
single RRD file, you can slice and dice the individual RRA's up in 
various ways at once for different views.

-jc