Writing Custom Data Input Scripts

[vhowell]

I have several Orinoco wireless access points that I want to be able to track the Signal Strength, Noise Strength, and SNR for each connection to the AP. I can do this via SNMP. However. In order to acomplish this I need to make changes to some OID values and test to see what the correct OID Number is for the connected user. These OID numbers change depending on how many are connected and when they connected or reconnected.
I have some ideas on how to accomplish this, but I do not know how the scripts work in Cacti. Could some one give me a quick overview.
Thanks
Van

[bulek]

vhowell,

It can be any script (shell, perl, php, etc.) or application that produces on standard output a value or set of values. Then when defining Data Input you have to enter properly formated output string.

You can look here:
http://www.raxnet.net/board/viewtopic.php?t=443

There is an example of using custom script producing three values. The script itself may be a helpful for you because for getting SNMP data it has to set some SNMP values before.

[vhowell]

Thanks,
That fixed the problem. I just setup a CDEF to multipy by 300 and now the graphed data corresponds with the data I actually get.
Another question.
How do I get RRD not to graph any 0 data or anything over 100. Any time I get 0 it is bad data so I do not want it graphed. Plus I am looking at a Percentage of Maximum signal stregnth so there should be no value greater than 100. From time to time I get a spike over 100 I'm not sure why.
Van

[bulek]

You can avoid collecting incorrect values by setting "Minimum Value" and "Maximum Value" in DS definition.

If you laready have "incorrect" data collected you can avoid graphing them by setting "Lower Limit" and "Upper Limit" in Graph definition.

Regards,
bulek