title: Change GKE storage class without losing content
body: <p>I've inherited a terraform/helm based GKE with a set of deployments and services in production environment. All of them use the default storage class as PVC.</p>
  <p>I would like to switch to a more robust way of storage (default retain or even Filestore+NFS). I was wondering if there is a way to switch the storage class to the newer ones <em>without</em> loosing or manually move the content from the oldest default volumes. This eventually using terraform and updating the Helm charts for consistency.</p>
  <p>Is there a way to do so?</p>