Disk & Filesystem Management (Du/Df/Lsblk/Fstrim)
Force your SSD to actually clear out its deleted blocks
🧩 The Challenge
You delete a massive log directory on a virtual machine, but the host still thinks the disk is full and refuses to provision more space. It is beyond annoying watching your hypervisor throw out-of-space alerts when you know for a fact the file is gone.
đź’ˇ The Fix
Manually invoke a discard operation to tell the SSD controller which blocks are ready for garbage collection. This clears the deck for the underlying hardware to reclaim space the OS thinks is still “in use”.
fstrim -av⚙️ Why It Works
Running this tells the filesystem to walk through all the unallocated blocks and send a trim command to the underlying storage hardware. Without this, your thin-provisioned disks stay bloated even if they have plenty of empty room.
🚀 Pro-Tip: Stick it in a weekly cron job if your distribution’s default systemd timer keeps failing.
Linux Tips & Tricks | © ngelinux.com | 10/13/2026