🧠 LVM Thin Provisioning with Auto Expansion on Ubuntu

This project provides a modular, production-ready setup to manage large, dynamically growing storage using LVM Thin Provisioning on Ubuntu. It enables you to start with minimal storage and expand on-the-fly by detecting and integrating new disks.

---

📌 Features

• Thin-provisioned logical volume (100TB virtual size by default)
• Automatically detects and adds new physical disks
• Expands thin pool without downtime
• Cron and systemd support for automation
• Optional .deb packaging and GitHub Actions CI

---

🛠️ Scripts Included

1. lvm_thinpool_initial_setup.sh

📁 Path: /usr/local/bin/lvm_thinpool_initial_setup.sh

🔧 One-time setup script:

• Initializes first disk (e.g., /dev/sdb)
• Creates:
  • Volume Group: vgthin
  • Thin Pool: thinpool
  • Metadata LV: thinmeta
  • Thin-provisioned LV: lvdata (default: 100TB)
• Formats and mounts LV to /data
• Adds to /etc/fstab

📦 Usage:

sudo /usr/local/bin/lvm_thinpool_initial_setup.sh

---

2. auto_detect_and_expand_thinpool.sh

📁 Path: /usr/local/bin/auto_detect_and_expand_thinpool.sh

🔁 Auto-detect and integrate new raw disks:

• Partitions new unpartitioned disks
• Creates PVs
• Adds them to Volume Group vgthin
• Expands thinpool using free space

📦 Usage:

sudo /usr/local/bin/auto_detect_and_expand_thinpool.sh

📆 Cron Automation:

sudo crontab -e
# Add:
@hourly /usr/local/bin/auto_detect_and_expand_thinpool.sh

🪵 Logs:

/var/log/lvm_auto_expand.log

---

📂 Filesystem Overview

Component	Purpose
/dev/vgthin/lvdata	Thin-provisioned Logical Volume
/data	Mount point for LV
/etc/fstab	Ensures auto-mount on reboot
/var/log/lvm_auto_expand.log	Log of expansion events

---

🔍 Monitoring Thin Pool Usage

Check thin pool usage:

sudo lvs -a

Detailed usage monitoring:

sudo lvs -o+seg_monitor,seg_size,data_percent,metadata_percent

⚠️ Watch data_percent and metadata_percent.
If either reaches 100%, I/O operations will fail.

---

📈 Disk Expansion Plan Example

Time	Action	VG Size	Thin Pool Size
Month 0	Initial setup (30GB disk)	30GB	~28GB
Month 6	Add 1x 4TB disk	4.03TB	~2TB
Month 12	Add 1x 4TB disk	8.03TB	~6TB
Month 18	Add 1x 4TB disk	12.03TB	~10TB

---

🧪 Requirements

• Ubuntu 20.04 or newer
• Packages: lvm2, parted, coreutils, cron
• Root privileges
• Clean (unpartitioned) disks for auto-detection

---

⚠️ Best Practices

• Always maintain 5–10% free space in the thin pool
• Set up alerts (email, Prometheus, etc.) for usage thresholds
• Monitor data_percent and metadata_percent regularly
• Avoid overcommitting disk without growth planning
• Always pre-test in staging or non-critical environments

---

🛠️ Optional Enhancements

Systemd Service & Timer (Alternative to Cron)

Create service unit:

sudo nano /etc/systemd/system/lvm-expand.service

[Unit]
Description=Auto Expand LVM Thin Pool
After=multi-user.target

[Service]
ExecStart=/usr/local/bin/auto_detect_and_expand_thinpool.sh

Create timer unit:

sudo nano /etc/systemd/system/lvm-expand.timer

[Unit]
Description=Run LVM Expansion Hourly

[Timer]
OnBootSec=10min
OnUnitActiveSec=1h

[Install]
WantedBy=timers.target

Enable and start the timer:

sudo systemctl daemon-reexec
sudo systemctl enable --now lvm-expand.timer

---

📦 Optional: .deb Package Structure

Project can be packaged for easier distribution:

my-lvm-expander/
├── DEBIAN
│   └── control
├── usr
│   └── local
│       └── bin
│           ├── lvm_thinpool_initial_setup.sh
│           └── auto_detect_and_expand_thinpool.sh
└── etc
    └── systemd
        └── system
            ├── lvm-expand.service
            └── lvm-expand.timer

Build the .deb:

dpkg-deb --build my-lvm-expander

---

🧪 GitHub Actions Test Workflow

Use this to lint and validate the shell scripts:

.github/workflows/test.yml:

name: Test LVM Expansion Scripts

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v3

      - name: Lint Shell Scripts
        uses: ludeeus/action-shellcheck@master

      - name: Ensure Scripts Are Executable
        run: |
          chmod +x ./lvm_thinpool_initial_setup.sh
          chmod +x ./auto_detect_and_expand_thinpool.sh
          echo "✅ Scripts are executable"

---

📜 License

MIT License — Free to use, modify, and distribute for personal and commercial use.

---

👨‍💻 Maintainer

Built and maintained by Hacky Coder 0951
Designed for scalable, cloud-ready Linux storage automation.