Multihost summary graphs -- how?

[pruesse]

I don't like the optics and it's inabillity to acquire data via snmp of ganglia, so I'm using cacti.

BUT, I can't seem to be able to find a way to easily create graphs that sum/average/max stats from a group of hosts. Manually, I can, but for dozens of hosts it's a pain to create the graphs manually. Is there any way to, say, create a virtual host that sums all data from a group of hosts? Or to create a graph template that I can just add a number of hosts to? I'd like to graph things like "how much of my clusters total memory is used right now?", "which are the five machines with the highest load? what is the difference between average and maximum cpu-load on that group of nodes?"

If it can't be done without php coding, how much work would you guess it would be for someone who knows a little php, but doesn't know cactis interna well? (How should it be done, where would I start?)

./regards
Elmar

[axelilly]

I think read about this same kind of issue somewhere else in the forum once. If I recall correcltly (and I may be very incorrect here), the answer was to create a CDEF that would add the select data sources together using the SUM operator.

I hope that may help to lead you in the right direction.

[TheWitness]

The real answer would be to select multiple Data Sources from the UI and then have a drop down pick for something like "Create Multiple Interface Graph".

TheWitness

[orsoone]

This taste of waste create a graph of download from 2 interfaces on WAN side, that are added in cacti and upload
there are 4 checkboxes > WAN1 IN - select wan interface on router - in / represent download
WAN2 IN - secondary WAN interface / backup connect or secondary peering point of network

WAN1&2 OUT wan interfaces direction out

I have used 2 very simple cdefs in this graf
first for sum WAN1 in and WAN2 in and turn into bits/s > a,b,+,8.*
second cdef for upload> c,d,+,8,*
i am using cacti 0.8.6.i
sory for my wery bad english