Book Image

Cacti Beginner's Guide - Second Edition

Book Image

Cacti Beginner's Guide - Second Edition

Overview of this book

Cacti is a performance measurement tool that provides easy methods and functions for gathering and graphing system data. You can use Cacti to develop a robust event management system that can alert on just about anything you would like it to. But to do that, you need to gain a solid understanding of the basics of Cacti, its plugin architecture, and automation concepts. Cacti Beginner's Guide will introduce you to the wide variety of features of Cacti and will guide you on how to use them for maximum effectiveness. Advanced topics such as the plugin architecture and Cacti automation using the command-line interface will help you build a professional performance measurement system. Designed as a beginner's guide, the book starts off with the basics of installing and using Cacti, and also covers the advanced topics that will show you how to customize and extend the core Cacti functionalities. The book offers essential tutorials for creating advanced graphs and using plugins to create enterprise-class reports to show your customers and colleagues. From data templates to input methods and plugin installation to creating your own customized plugins, this book provides you with a rich selection of step-by-step instructions to reach your goals. It covers all you need to know to implement professional performance measurement techniques with Cacti and ways to fully customize Cacti to fit your needs. You will also learn how to migrate Cacti to new servers. Lastly you will also be introduced to the latest feature of building a scalable remote poller environment. By the end of the book, you will be able to implement and extend Cacti to monitor, display, and report the performance of your network exactly the way you want.
Table of Contents (24 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
15
Online Resources

The Round Robin database tool


Cacti uses RRDtool to store and graph its performance data. RRD files store data in a fixed size file using a First In, First Out (FIFO) methodology and in order to aggregate data, different Round Robin Archives (RRA) are defined within a single RRD file. These RRAs usually consist of daily, weekly, monthly and yearly archives but can be freely defined.

The RRD file architecture

The principal of an RRD file is shown in the next figure. We have defined three Round Robin Archives, one storing 5 minute polling data, one RRA storing 20 minutes  (4 * 5 minute polling data) aggregated data and another one storing the hourly (12 * 5 minute polling data) aggregated data.

In this example, the data step is defined as 5 minutes (300 seconds) so updates to the RRD file should happen every 5 minutes. During each update, the data is being written to the first archive. After 20 minutes have passed, the first data set is aggregated and written to the 2nd archive so that it contains...