Cacti Graph Templates Explained: RRDTool Graphing Solution
How do I create Cacti Graph Templates? How do I display multiple data sources on one Cacti graph? What do all the Cacti options mean? What is a CDEF? I created a Cacti Graph but all of my data sources are displaying NAN, how do I troubleshoot that?
Cacti is a powerful RRDTool based graphing system typically used for graphing hardware and software data for historical reference. When I initially configured a Cacti Graph Template I found some of the options confusing but as you will see below they all make sense and typically the name explains each items function in a fairly easy way. Please post a comment if you have any further questions that are not answered or if I have made any answers feel free to use the contact form and point them out to me as I am trying to learn the best way to use Cacti just like everyone else. I repeat the same terms many times in this document simply for the fact to try and explain in detail what things mean. I did not want to start switching names with acronyms and vice verse to add confusion and to try and make this a very easy document to understand.
Below I do my best to explain what the Cacti Graph Templates mean and how to begin using them. First lets look at the Cacti admin console and how to get to the Graph Templates area.
First you need to create the Graph Template shell to plot your data sources on. You will need to enter the following two fields of data as shown by the arrows in the image below.
Graph Template Options
Name: Create a friendly name for the graph template itself.
Title: Here you can provide a title that will be included for any graph made using this Graph Template or you can check the Use Per-Graph Value if you want to provide a unique name per graph created.
Click “Create” after you have filled in the two options above.
Graph Template Items
A Graph Template Item needs to be created for each value you wanted to display on the graph. Here are the options for creating a graph template item in the order they are entered into the Graph Template admin area.
- Data Source is where you specify where the data is coming from. Say you are creating a Cacti Graph Template for Postgres table sizes then you would specify the data source from the data template you either created or imported into Cacti as listed below.
- An easy example is to look at the “Unix – Hard Drive Space” space that is installed with Cacti by default. If you were creating the graph template for this data template you would be adding two data sources to this graph and they would be “Unix – Hard Drive Space (hdd_free)” and “Unix – Hard Drive Space (hdd_used)”. Simply put the data source is the number that is graphed such as in this scenario it might be 73014444032 (which is in Bytes) for hdd_free if you had 68GB of disk space left. Below we talk more about how the actual data source is displayed.