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

Stop wondering why your mount points are hiding their true size

🧩 The Challenge

Ever been paged because a disk is supposedly full, but `df` shows 50% capacity while the directories seem completely empty? It’s usually some zombie file handle sitting on a deleted log file that the kernel refuses to release.

💡 The Fix

Use lsof to hunt down those hidden file descriptors that are still hogging the space after you deleted the actual file. It’s the only way to see what the filesystem is actually holding onto.

lsof +L1

⚙️ Why It Works

This flags files that have a link count of less than 1, meaning they are deleted but still kept open by a process that hasn’t closed the descriptor yet. Restarting the service holding these handles will instantly reclaim the space.

🚀 Pro-Tip: Always check this before you go nuking other directories in a panic.

Linux Tips & Tricks | © ngelinux.com | 7/17/2026