title: Does docker container maintain volume data?
body: <p>This might come across as a stupid question, but I am unable to figure something about docker volumes. Going through the <a href="https://docs.docker.com/storage/volumes/" rel="nofollow noreferrer">official documentation</a> I can see that we can map the host machine file system on the container for persistent storage. Following the instruction I was successfully able to mount a folder on my container.</p>
  <p>Once I exec bash into the container, I can see the mapped directory structure there as expected. My question is, how is the data mapped between these two paths, that is from the container to the mount volume on host OS. Is the data duplicated or the container directly stores the data on the volume on host OS and the mapped paths are shown for something like symlink ?</p>
  <p>This question comes across since we are trying to maintain a large amount of data on a mounted disk but accessible by the container, with the assumption that mounting volume would directly store the data on the disk and nothing on the container.</p>