# Knowledge Check: Storage and Filesystems --- **1. `df -h /` shows only 23% used, but you suspect one directory is unusually large. Does `df` alone answer that?** *Answer:* No — `df` reports overall filesystem usage, not per-directory. You need `du -sh ` pointed at the suspect directory (or directories) to answer that. --- **2. What makes data in a container's writable layer different from data in `/home`?** *Answer:* By convention and design, a container's own writable layer is meant to be disposable — data there disappears when the container is destroyed, unless explicitly persisted elsewhere (a topic ROOT 04 covers directly). `/home` data is expected to persist normally. --- **3. What does "mounting" a filesystem actually mean?** *Answer:* Attaching a filesystem so it becomes accessible at a specific directory path — `/` itself is a mount point, and additional filesystems can be mounted at other paths. ## Instructor Notes **Facilitation:** Question 2 previews ROOT 04's volume/bind-mount content directly — worth naming that connection explicitly. **Approximate timing:** 5 minutes.