<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Data Storage</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="Principles of Operation" HREF="operating_principles.html"><LINK REL="PREVIOUS" TITLE="Principles of Operation" HREF="operating_principles.html"><LINK REL="NEXT" TITLE="Data Presentation" HREF="data_presentation.html"><LINK REL="STYLESHEET" TYPE="text/css" HREF="manual.css"></HEAD ><BODY CLASS="SECT1" 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="operating_principles.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 5. Principles of Operation</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="data_presentation.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="DATA_STORAGE" >Data Storage</A ></H1 ><P > There are lots of different approaches for this task. Some may use an (SQL) database, others flat files. Cacti uses <A HREF="http://www.rrdtool.org/" TARGET="_top" ><SPAN CLASS="APPLICATION" >RRDTool</SPAN > </A > to store data. </P ><P > RRD is the acronym for Round Robin Database. RRD is a system to store and display time-series data (i.e. network bandwidth, machine-room temperature, server load average). It stores the data in a very compact way that will not expand over time, and it can create beautiful graphs. This keeps storage requirements at bay. </P ><P > Likewise, rrdtool will perform some specific tasks. It performs consolidation to combine raw data (a primary data point in rrdtool lingo) to consolidated data (a consolidated data point). This way, historical data is compressed to save space. rrdtool knows different consolidation functions: AVERAGE, MAXIMUM, MINIMUM and LAST. </P ></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="operating_principles.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_presentation.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Principles of Operation</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="operating_principles.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Data Presentation</TD ></TR ></TABLE ></DIV ></BODY ></HTML >