title: When to use auto mapped Docker data volume
body: <p>What is the main purpose of Docker data volume created by -v option without specified host file? For example <code>docker run -v /data -ti my-image</code>. Doc says it creates a new filesystem mapped to host filesystem to persist data (at some random-ish location). I understand that. But containers also persist all data when they are stopped and started again. So what is the difference between persisted data in stopped container vs. data volume? </p>
  
  <p>I understand use-case for its advanced usage to map specific host file with <code>-v /data:/data/host</code>.</p>