<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Principles of Operation</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="The Cacti Manual" HREF="index.html"><LINK REL="UP" TITLE="Basics" HREF="basics.html"><LINK REL="PREVIOUS" TITLE="Basics" HREF="basics.html"><LINK REL="NEXT" TITLE="Data Storage" HREF="data_storage.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="manual.css"></HEAD ><BODY CLASS="CHAPTER" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >The Cacti Manual</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="basics.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="data_storage.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="OPERATING_PRINCIPLES" ></A >Chapter 5. Principles of Operation</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT ><A HREF="operating_principles.html#DATA_RETRIEVAL" >Data Retrieval</A ></DT ><DT ><A HREF="data_storage.html" >Data Storage</A ></DT ><DT ><A HREF="data_presentation.html" >Data Presentation</A ></DT ></DL ></DIV ><P > Cacti operation may be divided into three different tasks: </P ><DIV CLASS="FIGURE" ><A NAME="PRINCIPLES_OF_OPERATION" ></A ><P ><B >Figure 5-1. Principles of Operation</B ></P ><DIV CLASS="MEDIAOBJECT" ><P ><IMG SRC="images/principles_of_operation.png"></P ></DIV ></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="DATA_RETRIEVAL" >Data Retrieval</A ></H1 ><P > First task is to retrieve data. Cacti will do so using its Poller. The Poller is executed from the operating system's scheduler, e.g. crontab for Unix flavored OSes. </P ><P > In current IT installations, you're dealing with lots of devices of different kind, e.g. servers, network equipment, appliances and the like. To retrieve data from remote targets/hosts, cacti will mainly use the Simple Network Management Protocol SNMP. Thus, all devices capable of using SNMP will be eligible to be monitored by cacti. </P ><P > Later on, we demonstrate how to extend cacti's capabilities of retrieving data to scripts, script queries and more. </P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="basics.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="data_storage.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Basics</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="basics.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Data Storage</TD ></TR ></TABLE ></DIV ></BODY ></HTML >