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<body style="background-color: white">
-<p><a name="__index__"></a></p>
+
<!-- INDEX BEGIN -->
+<div name="index">
+<p><a name="__index__"></a></p>
<!--
<ul>
<li><a href="#rrd_server">RRD Server</a></li>
</ul>
+ <li><a href="#rrdcached__the_caching_daemon">RRDCACHED, THE CACHING DAEMON</a></li>
<li><a href="#see_also">SEE ALSO</a></li>
<li><a href="#bugs">BUGS</a></li>
<li><a href="#author">AUTHOR</a></li>
</ul>
+
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+</div>
<!-- INDEX END -->
<p>
saves a considerable amount of startup time when you plan to make
<strong>RRDtool</strong> do a lot of things quickly. Check the section on <em>Remote_Control</em>
further down. There is also a number of language bindings
-for RRDtool which allow you to use it directly from perl, python, tcl,
-php, etc.</p>
+for RRDtool which allow you to use it directly from Perl, python, Tcl,
+PHP, etc.</p>
<dl>
-<dt><strong><a name="item_create"><strong>create</strong></a></strong></dt>
+<dt><strong><a name="create" class="item"><strong>create</strong></a></strong></dt>
<dd>
<p>Set up a new Round Robin Database (RRD). Check <a href="././rrdcreate.html">the rrdcreate manpage</a>.</p>
</dd>
-<dt><strong><a name="item_update"><strong>update</strong></a></strong></dt>
+<dt><strong><a name="update" class="item"><strong>update</strong></a></strong></dt>
<dd>
<p>Store new data values into an RRD. Check <a href="././rrdupdate.html">the rrdupdate manpage</a>.</p>
</dd>
-<dt><strong><a name="item_updatev"><strong>updatev</strong></a></strong></dt>
+<dt><strong><a name="updatev" class="item"><strong>updatev</strong></a></strong></dt>
<dd>
<p>Operationally equivalent to <strong>update</strong> except for output. Check <a href="././rrdupdate.html">the rrdupdate manpage</a>.</p>
</dd>
-<dt><strong><a name="item_graph"><strong>graph</strong></a></strong></dt>
+<dt><strong><a name="graph" class="item"><strong>graph</strong></a></strong></dt>
<dd>
<p>Create a graph from data stored in one or several RRDs. Apart from
generating graphs, data can also be extracted to stdout. Check <a href="././rrdgraph.html">the rrdgraph manpage</a>.</p>
</dd>
-<dt><strong><a name="item_dump"><strong>dump</strong></a></strong></dt>
+<dt><strong><a name="dump" class="item"><strong>dump</strong></a></strong></dt>
<dd>
<p>Dump the contents of an RRD in plain ASCII. In connection with restore
you can use this to move an RRD from one computer architecture to
another. Check <a href="././rrddump.html">the rrddump manpage</a>.</p>
</dd>
-<dt><strong><a name="item_restore"><strong>restore</strong></a></strong></dt>
+<dt><strong><a name="restore" class="item"><strong>restore</strong></a></strong></dt>
<dd>
<p>Restore an RRD in XML format to a binary RRD. Check <a href="././rrdrestore.html">the rrdrestore manpage</a></p>
</dd>
-<dt><strong><a name="item_fetch"><strong>fetch</strong></a></strong></dt>
+<dt><strong><a name="fetch" class="item"><strong>fetch</strong></a></strong></dt>
<dd>
<p>Get data for a certain time period from a RRD. The graph function
uses fetch to retrieve its data from an RRD. Check <a href="././rrdfetch.html">the rrdfetch manpage</a>.</p>
</dd>
-<dt><strong><a name="item_tune"><strong>tune</strong></a></strong></dt>
+<dt><strong><a name="tune" class="item"><strong>tune</strong></a></strong></dt>
<dd>
<p>Alter setup of an RRD. Check <a href="././rrdtune.html">the rrdtune manpage</a>.</p>
</dd>
-<dt><strong><a name="item_last"><strong>last</strong></a></strong></dt>
+<dt><strong><a name="last" class="item"><strong>last</strong></a></strong></dt>
<dd>
<p>Find the last update time of an RRD. Check <a href="././rrdlast.html">the rrdlast manpage</a>.</p>
</dd>
-<dt><strong><a name="item_info"><strong>info</strong></a></strong></dt>
+<dt><strong><a name="info" class="item"><strong>info</strong></a></strong></dt>
<dd>
<p>Get information about an RRD. Check <a href="././rrdinfo.html">the rrdinfo manpage</a>.</p>
</dd>
-<dt><strong><a name="item_rrdresize"><strong>rrdresize</strong></a></strong></dt>
+<dt><strong><a name="rrdresize" class="item"><strong>rrdresize</strong></a></strong></dt>
<dd>
<p>Change the size of individual RRAs. This is dangerous! Check <a href="././rrdresize.html">the rrdresize manpage</a>.</p>
</dd>
-<dt><strong><a name="item_xport"><strong>xport</strong></a></strong></dt>
+<dt><strong><a name="xport" class="item"><strong>xport</strong></a></strong></dt>
<dd>
-<p>Export data retrieved from one or several RRDs. Check <a href="././rrdxport.html">the rrdxport manpage</a></p>
+<p>Export data retrieved from one or several RRDs. Check <a href="././rrdxport.html">the rrdxport manpage</a>.</p>
</dd>
-<dt><strong><a name="item_rrdcgi"><strong>rrdcgi</strong></a></strong></dt>
+<dt><strong><a name="flushcached" class="item"><strong>flushcached</strong></a></strong></dt>
+
+<dd>
+<p>Flush the values for a specific RRD file from memory. Check <a href="././rrdflushcached.html">the rrdflushcached manpage</a>.</p>
+</dd>
+<dt><strong><a name="rrdcgi" class="item"><strong>rrdcgi</strong></a></strong></dt>
<dd>
<p>This is a standalone tool for producing RRD graphs on the fly. Check
@@ -152,7 +164,7 @@ uses fetch to retrieve its data from an RRD. Check <a href="././rrdfetch.html">t
</p>
<h2><a name="how_does_rrdtool_work">HOW DOES RRDTOOL WORK?</a></h2>
<dl>
-<dt><strong><a name="item_data_acquisition">Data Acquisition</a></strong></dt>
+<dt><strong><a name="data_acquisition" class="item">Data Acquisition</a></strong></dt>
<dd>
<p>When monitoring the state of a system, it is convenient to have the
always be able to fetch data at exactly the time you want
to. Therefore <strong>RRDtool</strong> lets you update the logfile at any time you
want. It will automatically interpolate the value of the data-source
-(<strong>DS</strong>) at the latest official time-slot (intervall) and write this
+(<strong>DS</strong>) at the latest official time-slot (interval) and write this
interpolated value to the log. The original value you have supplied is
stored as well and is also taken into account when interpolating the
next log entry.</p>
</dd>
-<dt><strong><a name="item_consolidation">Consolidation</a></strong></dt>
+<dt><strong><a name="consolidation" class="item">Consolidation</a></strong></dt>
<dd>
<p>You may log data at a 1 minute interval, but you might also be
different consolidation setups within one <strong>RRD</strong>. They will all be
maintained on the fly when new data is loaded into the <strong>RRD</strong>.</p>
</dd>
-<dt><strong><a name="item_round_robin_archives">Round Robin Archives</a></strong></dt>
+<dt><strong><a name="round_robin_archives" class="item">Round Robin Archives</a></strong></dt>
<dd>
<p>Data values of the same consolidation setup are stored into Round
one minute traffic on the LAN, the minimum temperature of your wine cellar,
the total minutes of down time, etc.</p>
</dd>
-<dt><strong><a name="item_unknown_data">Unknown Data</a></strong></dt>
+<dt><strong><a name="unknown_data" class="item">Unknown Data</a></strong></dt>
<dd>
<p>As mentioned earlier, the <strong>RRD</strong> stores data at a constant
data point is above a configurable level. If not, an <em>*UNKNOWN*</em> value
will be written to the <strong>RRA</strong>.</p>
</dd>
-<dt><strong><a name="item_graphing">Graphing</a></strong></dt>
+<dt><strong><a name="graphing" class="item">Graphing</a></strong></dt>
<dd>
<p><strong>RRDtool</strong> allows you to generate reports in numerical and
contents of the graph can be defined freely. Check <a href="././rrdgraph.html">the rrdgraph manpage</a>
for more information on this.</p>
</dd>
-<dt><strong><a name="item_aberrant_behavior_detection">Aberrant Behavior Detection</a></strong></dt>
+<dt><strong><a name="aberrant_behavior_detection" class="item">Aberrant Behavior Detection</a></strong></dt>
<dd>
<p>by Jake Brutlag</p>
coefficient (a periodic effect, such as a daily cycle). There is one
seasonal coefficient for each time point in the period (cycle). After
a value is observed, each of these components is updated via
-exponential smoothing. This means that the algorithm ``learns'' from
+exponential smoothing. This means that the algorithm "learns" from
past values and uses them to predict the future. The rate of
adaptation is governed by 3 parameters, alpha (intercept), beta
(slope), and gamma (seasonal). The prediction can also be viewed as a
<strong>s:</strong><em>systemtime</em>. Both values are the running totals of seconds since
RRDtool was started. If an error occurs, a line of the form '<code>ERROR:</code>
<em>Description of error</em>' will be printed instead. <strong>RRDtool</strong> will not abort,
-unless something realy serious happens. If
+unless something really serious happens. If
a <strong>workdir</strong> is specified and the UID is 0, RRDtool will do a chroot to that
workdir. If the UID is not 0, RRDtool only changes the current directory to
<strong>workdir</strong>.</p>
rrdsrv stream tcp nowait root /opt/rrd/bin/rrdtool rrdtool - /var/rrd</pre>
<p>Don't forget to create the database directory /var/rrd and
reinitialize your inetd.</p>
-<p>If all was setup correctly, you can access the server with perl
+<p>If all was setup correctly, you can access the server with Perl
sockets, tools like netcat, or in a quick interactive test by using
'telnet localhost rrdsrv'.</p>
<p><strong>NOTE:</strong> that there is no authentication with this feature! Do not setup
<p>
</p>
<hr />
+<h1><a name="rrdcached__the_caching_daemon">RRDCACHED, THE CACHING DAEMON</a></h1>
+<p>For very big setups, updating thousands of RRD files often becomes a serious IO
+problem. If you run into such problems, you might want to take a look at
+<a href="././rrdcached.html">the rrdcached manpage</a>, a caching daemon for RRDTool which may help you lessen the
+stress on your disks.</p>
+<p>
+</p>
+<hr />
<h1><a name="see_also">SEE ALSO</a></h1>
-<p>rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrdtune, rrdlast, rrdxport</p>
+<p>rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrdtune, rrdlast, rrdxport,
+rrdflushcached, rrdcached</p>
<p>
</p>
<hr />