Disk & Filesystem Management (Du/Df/Lsblk/Fstrim)

Stop guessing what is actually eating your mount points

🧩 The Challenge

Dealing with a production server where df says you are out of space, but du claims the directories are empty is a special kind of hell. I’ve spent whole nights hunting down hidden mount points that were masking massive log files.

💡 The Fix

Use findmnt to verify exactly what is mounted where instead of trusting the vague output of df or the file system tree. This saves you from hunting for ghost files that don’t exist in the current directory.

findmnt --target /path/to/suspect/directory

⚙️ Why It Works

This command queries the kernel’s list of mounts directly, bypassing the confusion that happens when you mount a filesystem over a non-empty directory. It reveals the true hierarchy of your storage so you stop chasing shadows.

🚀 Pro-Tip: Pipe it into grep if you are dealing with a massive list of bind mounts or containers.

Linux Tips & Tricks | © ngelinux.com | 7/15/2026