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<section id="the-process-count-keeps-growing">
<h1>The process count keeps growing!<a class="headerlink" href="#the-process-count-keeps-growing" title="Permalink to this heading"></a></h1>
<p>If you notice that your imapd process count continues to grow and never decreases, there are a number of options which may be affecting it.</p>
<section id="reuse-count">
<h2>1. Reuse count<a class="headerlink" href="#reuse-count" title="Permalink to this heading"></a></h2>
<p>By default, imapd processes will remain alive for 250 new connections before shutting down. Setting this to a lower value will reduce the amount of time unused processes hang around. There is a tradeoff between startup/shutdown overhead and process longevity.</p>
<p>The use setting is the <strong>- U</strong> argument to <a class="reference internal" href="../manpages/systemcommands/imapd.html#std-cyrusman-imapd-8">imapd(8)</a>.</p>
</section>
<section id="maximum-child-count">
<h2>2. Maximum child count<a class="headerlink" href="#maximum-child-count" title="Permalink to this heading"></a></h2>
<p>By default, Cyrus is allowed to spawn a limitless number of child imapd processes. To control this growth, adjust the <strong>maxchild</strong> option in <a class="reference internal" href="../manpages/configs/cyrus.conf.html#std-cyrusman-cyrus.conf-5">cyrus.conf(5)</a>.</p>
</section>
<section id="clean-up-connections-that-are-no-longer-in-use">
<h2>3. Clean up connections that are no longer in use<a class="headerlink" href="#clean-up-connections-that-are-no-longer-in-use" title="Permalink to this heading"></a></h2>
<p>While POP connections are short lived, IMAP connections can be long lived. And then there are processes trying to listen to a client that's no longer alive.</p>
<p>Setting <strong>tcp_keepalive</strong> option in <a class="reference internal" href="../manpages/configs/imapd.conf.html#std-cyrusman-imapd.conf-5">imapd.conf(5)</a> to <strong>1</strong> can be used to test if connections are still alive. The operating system will send an ACK packet every so often (every 2 hours by default on Linux) which tests if the TCP endpoint is still reachable.</p>
<p>The other <strong>tcp_keepalive_</strong> options help control how and when the test occurs.</p>
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