tly.</p>
</li>
<li>
<p>There can be many billions of function instances in a single StateFun cluster.</p>
</li>
</ul>
<p>To model our use case, we&rsquo;ll define three functions: <strong>ServerFun</strong>, <strong>RackFun</strong> and <strong>DataCenterFun</strong>.</p>
<p><strong>ServerFun</strong></p>
<p>Each physical server is represented with its <em>digital twin</em> stateful function. This function is responsible for:</p>
<ol>
<li>
<p>Maintaining a sliding window of incoming metrics.</p>
</li>
<li>
