more exact graph, possible?

[dude4you]

normaly a graph is about 1 day long. when i set the cmd.php to 30seconds
interval, can i get cacti to show me one graph which is 1 hour long?

I just want to graph the performance of my computer (cpu, mysql, sendmail,etc....) when executeing a programm on my server for about 2 minutes.

[Bisonlux]

Hi,

The formula used in the PHP script for calculating the timspan of a graph is :

Timespan = -(rows * steps * 144) [sec]

For example Rows=600; Steps=1; Timespan= -86400 sec, then the graph is shown from now-86400 seconds (1 day) to now.

So if you want to show only a few minutes try Catistoric (add-on to zoom a graph)

Good luck,

[dude4you]

what is catistoric? I actually want to graph real time. We want to protocol the behavier of our sever when the programm is running, which leasts for about 20 seconds. Should I better use a regular monitoring Tool for that purpose?

[Bisonlux]

Cacti take a sample all 5 minutes and put it in the rrd file. This is done by the cmd.php launched by the crontab all 5 minutes.

You can reduce it to run all minute (don’t forget to adjust your row, steps, ... in Cacti) .

If you want more precision it’s always possible put you must develop or find a trick to update your rrd files without cmd.php (I use a perl script). The minimum step required between to values for rrd is 1 second. In my opinion you can use rrd and Cacti to get the result expected but you must change or develop some code...

[dude4you]

Thanks

Cacti is running fine right now, but I will start making this changes in about 2 weeks. I hope I can drop questions to you if i got some.