How would that work when there are varying numbers of interfaces? I have 14 on one, and 10 on another, each interface in its own RRD being collected by MRTG. If I put all 14 in, won't it break on the 10?
Scot Kreienkamp skreien at la-z-boy.com
-----Original Message----- From: xymon-bounces at xymon.com [mailto:xymon-bounces at xymon.com] On Behalf Of Henrik Størner Sent: Thursday, October 13, 2011 1:42 PM To: xymon at xymon.com Subject: Re: [Xymon] monitoring aggregated network traffic
On 13-10-2011 16:44, netz-haut - stephan seitz wrote:
is there any "usual" way, to monitor and graph the traffic of a bulk of network interfaces? The reason is, some of our hosts are connected to iSCSI storages via multipath over two or four independent interfaces. Since the traffic is balanced equally, every interface shows (more or less) the same amount of traffic. This leads to very useless rrdtool graphics as there is only one multicolored thick line visible. It would be really helpful to see a graph which shows the SUM of the particular interfaces.
This can be done by creating an RRD graph definition to do the summation for you.
In RRDtool, you first use one or more "DEF" lines to grab specific data items from one or more RRD files, and put them into some "variables". You can then either use these variables directly to make a line on the graph, or you can use them for calculating other variables via a "CDEF" line.
The default ifstat graph has these lines:
DEF:inbytes at RRDIDX@=@RRDFN@:bytesReceived:AVERAGE
CDEF:in at RRDIDX@=inbytes at RRDIDX@,8,*(The @RRDIDX@ and @RRDFN@ are because this graph repeats over all the interfaces - Xymon replaces these with a number and the RRD filename).
What this does is to first define a variable "inbytes at RRDIDX@" which has the "bytesReceived" value from the RRD. The it computes another variable, "in at RRDIDX@" as 8*inbytes - to convert from bytes to bits. The notation here is Reverse Polish (RPN).
So if you have 4 RRD files, one for each interface, you can have RRDtool do the math for you like this:
[ifsum] TITLE Network Traffic YAXIS Bits/second DEF:inbytes0=ifstat.eth0.rrd:bytesReceived:AVERAGE DEF:inbytes1=ifstat.eth1.rrd:bytesReceived:AVERAGE DEF:inbytes2=ifstat.eth2.rrd:bytesReceived:AVERAGE DEF:inbytes3=ifstat.eth3.rrd:bytesReceived:AVERAGE CDEF:intotal=inbytes0,inbytes1,inbytes2,inbytes3,+,+,+ CDEF:inbits=intotal,8,* LINE:inbits#FF0000:Aggregate inbound
The "LINE" definition then uses the "inbits" value to draw a (red) line with this data.
Have a look at graphs.cfg, and I'm sure you can figure out to add a line for the outgoing data also.
Add "ifsum" to the GRAPHS setting in xymonserver.cfg, and the graph should show up on the "trends" page.
Regards, Henrik
PS: I haven't actually tested any of this, so feel free to provide corrections :-)
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