title: Azure App Service Architecture understanding: Per-App Scaling
body: <p>Regarding this MSDN article; <a href="https://msdn.microsoft.com/en-us/magazine/mt793270" rel="nofollow noreferrer">https://msdn.microsoft.com/en-us/magazine/mt793270</a></p>
  <p><strong>Per-App Scaling</strong> section has below paragraphs.</p>
  <blockquote>
  <p>Using the earlier 50 app example, with per-app scaling enabled for the App Service Plan, all 50 apps can be assigned to the same App Service Plan. Then, the scaling characteristics of individual apps can be modified:</p>
  <ul>
  <li>40 low-volume applications set to run on a maximum of a single server each.</li>
  <li>Five mid- to low-volume applications set to run on a maximum of two servers each.</li>
  <li>Five remaining high-volume applications set to run on a maximum of 10 servers.</li>
  </ul>
  <p>The underlying App Service Plan can start out with a minimum of five servers. And then auto-scale rules can be set to scale out as needed based on memory pressure vs. CPU.</p>
  </blockquote>
  <p>I cannot understand why above three configuration gives <em>minimum of five</em> servers as a starting count.</p>
  <p>Does it say 40 low-volume apps to 1 server, 5 mid-volume apps to 1 servers, and rest 5 high-volume apps to (undescribed) 3 servers?</p>