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  <div class="section" id="cassandra-topologies-properties-file">
<span id="cassandra-topology"></span><h1>cassandra-topologies.properties file<a class="headerlink" href="#cassandra-topologies-properties-file" title="Permalink to this headline">¶</a></h1>
<p>The <code class="docutils literal notranslate"><span class="pre">PropertyFileSnitch</span></code> <span class="xref std std-term">snitch</span> option uses the <code class="docutils literal notranslate"><span class="pre">cassandra-topologies.properties</span></code> configuration file to determine which <span class="xref std std-term">datacenters</span> and racks cluster nodes belong to. If other snitches are used, the
:ref:cassandra_rackdc must be used. The snitch determines network topology (proximity by rack and datacenter) so that requests are routed efficiently and allows the database to distribute replicas evenly.</p>
<p>Include every node in the cluster in the properties file, defining your datacenter names as in the keyspace definition. The datacenter and rack names are case-sensitive.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">cassandra-topologies.properties</span></code> file must be copied identically to every node in the cluster.</p>
<div class="section" id="example">
<h2>Example<a class="headerlink" href="#example" title="Permalink to this headline">¶</a></h2>
<p>This example uses three datacenters:</p>
<div class="highlight-bash notranslate"><div class="highlight"><pre><span></span><span class="c1"># datacenter One</span>

<span class="m">175</span>.56.12.105<span class="o">=</span>DC1:RAC1
<span class="m">175</span>.50.13.200<span class="o">=</span>DC1:RAC1
<span class="m">175</span>.54.35.197<span class="o">=</span>DC1:RAC1

<span class="m">120</span>.53.24.101<span class="o">=</span>DC1:RAC2
<span class="m">120</span>.55.16.200<span class="o">=</span>DC1:RAC2
<span class="m">120</span>.57.102.103<span class="o">=</span>DC1:RAC2

<span class="c1"># datacenter Two</span>

<span class="m">110</span>.56.12.120<span class="o">=</span>DC2:RAC1
<span class="m">110</span>.50.13.201<span class="o">=</span>DC2:RAC1
<span class="m">110</span>.54.35.184<span class="o">=</span>DC2:RAC1

<span class="m">50</span>.33.23.120<span class="o">=</span>DC2:RAC2
<span class="m">50</span>.45.14.220<span class="o">=</span>DC2:RAC2
<span class="m">50</span>.17.10.203<span class="o">=</span>DC2:RAC2

<span class="c1"># datacenter Three</span>

<span class="m">172</span>.106.12.120<span class="o">=</span>DC3:RAC1
<span class="m">172</span>.106.12.121<span class="o">=</span>DC3:RAC1
<span class="m">172</span>.106.12.122<span class="o">=</span>DC3:RAC1

<span class="c1"># default for unknown nodes</span>
<span class="nv">default</span> <span class="o">=</span>DC3:RAC1
</pre></div>
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