title: Understanding results of mongostat
body: <p>I am trying to understand the results of mongostat:</p>
  
  <p>example</p>
  
  <pre><code>insert  query update delete getmore command flushes mapped  vsize    res faults locked % idx  
  0      2      4      0       0      10       0   976m  2.21g   643m      0      0.1          0       
  0      1      0      0       0       4       0   976m  2.21g   643m      0        0          0       
  0      0      0      0       0       1       0   976m  2.21g   643m      0        0          0    
  </code></pre>
  
  <p>I see</p>
  
  <pre><code>mapped - 976m
  vsize-2.2.g
  res - 643m
  </code></pre>
  
  <ul>
  <li><code>res</code> - RAM, so ~650MB of my database is in RAM</li>
  <li><code>mapped</code> - total size of database (via memory mapped files)</li>
  <li><code>vsize</code> - ???</li>
  </ul>
  
  <p>not sure why vsize is important or what exactly it means in this content - im running an m1.large so i have like 400GB of HD space + 8GB of RAM.</p>
  
  <p>Can someone help me out here and explain if </p>
  
  <ol>
  <li>I am on the right page</li>
  <li>what stats I should monitor in production</li>
  </ol>