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

Stop df from lying to you about your actual free space

🧩 The Challenge

You ever run df -h and see 100% usage, but when you go hunting for big files with du, the numbers don’t add up? It’s infuriating because you end up staring at a server that claims it’s full while half the disk space is just missing in action.

💡 The Fix

Most of the time, some background process is holding onto a deleted log file that is still hogging the blocks, so you need to find those open descriptors to see what is really eating your storage.

lsof +L1 | grep deleted

⚙️ Why It Works

By searching for files that have been unlinked but are still held open by a PID, you can pinpoint exactly which service needs a restart to release the space back to the filesystem.

🚀 Pro-Tip: Always check the grep output for giant log files before you just start bouncing services blindly.

Linux Tips & Tricks | © ngelinux.com | 8/16/2026