more frequent polling


31-07-2003 22:12:31

Hi folks,

I understand that development is still pretty early in NetMRG, but I'm impressed with the polish of the app already. I'm currently a cacti user and one of my frustrations with that product is its slow poller and the difficulty in changing the default step of the program.

Alot of the traffic I deal with is bursty, and with 5 minute sample intervals, you lose those characteristics.

Ideally I would like to poll some of my devices at 1 minute intervals. I think it would be really cool if I didn't have to poll _every_ device at that interval, but with a fast poller it shouldn't matter so much.

So, I guess my questions are

1. How would I go about setting up a faster polling interval in NetMRG?

2. Could you make it a feature of NetMRG to poll devices at different intervals, or at least make it simple to change the default interval for the entire application?



31-07-2003 23:17:11

It should be easy to change the interval globally. Up to this point, we've not looked into per-device specifications of the interval. It's certainly worth considering.

I've not verified the following changes on a live setup, but the following code replaced into rrd.cpp should give you a proper setup for 1-minute intervals

command = "create " + get_rrd_file(inttostr(info.monitor_id)) +
" --step 60 DS:mon_" + inttostr(info.monitor_id) + ":" + rrd.data_type +
":120:" + rrd.min_val + ":" + rrd.max_val + " " +
"RRA:AVERAGE:0.5:1:3000 " +
"RRA:AVERAGE:0.5:30:700 " +
"RRA:AVERAGE:0.5:24:775 " +
"RRA:AVERAGE:0.5:288:797 " +
"RRA:LAST:0.5:1:3000 " +
"RRA:LAST:0.5:30:700 " +
"RRA:LAST:0.5:24:775 " +
"RRA:LAST:0.5:288:797 " +
"RRA:MAX:0.5:1:3000 " +
"RRA:MAX:0.5:30:700 " +
"RRA:MAX:0.5:24:775 " +

Your existing RRD files will not benefit from this change. You'll need to either delete them (they will be recreated with the new specs above) or use RRDTOOL's tune command to change their geometry to the above.

You might also want to change the default graph start times (or sizes) to give you sufficient resolution.

Good luck! Let us know how you make out.


15-09-2003 11:46:46

Refiguring things, I'm pretty sure the above code will have problems beyond a daily interval. However, 0.10pre2 has code that allows you to specify the interval in the config file, which will cause the RRD information to be recalculated. The same warning applies to changing the interval though, as it only applies to newly-created RRDs.

This should be a lot easier than tweaking the code. If you have successes or failures regarding faster polling, please let us know.