Emergency Disk Recovery & LVM Expansion Guide

1. Emergency: Freeing Space for Utilities

If the disk is 100% full, apt cannot download the tools required to fix the problem.

Case A: Manual Cleanup

Clear the package cache and old logs to gain immediate breathing room:

sudo apt-get clean
sudo apt-get autoremove -y
sudo journalctl --vacuum-size=50M

Case B: The RAM Disk Hack

If cleanup isn't enough, mount 50MB of RAM over the apt archives folder to allow package downloads:

sudo mount -t tmpfs -o size=50m tmpfs /var/cache/apt/archives

2. Expanding Partitions (Non-LVM)

Use growpart to expand a partition within an existing disk (e.g., after increasing a virtual disk size in your hypervisor).

Installation

sudo apt update
sudo apt install cloud-guest-utils -y

Execution

• Identify: Use lsblk to check your disk (e.g., /dev/sda) and partition number (e.g., 1).
• Grow:

# Note the space between device and partition number
sudo growpart /dev/sda 1

3. LVM Management (Adding New Capacity)

Use this workflow to add a new partition or unallocated space from /dev/sda into an existing Volume Group.

sudo pvcreate /dev/sdaX  # Replace X with your partition number

sudo vgextend <your-vg-name> /dev/sdaX

# Add all available free space from the VG to the LV
sudo lvextend -l +100%FREE /dev/mapper/your--lv--path

4. Final Step: Resizing the Filesystem

The partition and LVM are now larger, but the filesystem must be "stretched" to see the space.

Summary of Commands

• lsblk: View disk/partition structure.
• pvs / vgs / lvs: View LVM status.
• df -h: Check available disk space and filesystem types.
• tune2fs -m 1 /dev/sda1: (Emergency) Reduce root reserved space to 1% to free up space.