Deploy Flexible ZFS Storage with Mixed Disks Sizes

If you’re building a homelab, backup server, or expandable NAS using mixed-size hard drives, combining Ubuntu Server with ZFS is one of the most powerful and reliable solutions available today. This guide walks through deploying a ZFS pool using uneven disk sizes, enabling automated maintenance, and integrating everything into Webmin for easier management. Based on the deployment guide provided in the uploaded document

Why Use ZFS with Uneven Disks?

Traditional RAID solutions often struggle with drives that are different sizes. ZFS offers much more flexibility by allowing you to combine mirrored drives with single disks inside the same storage pool.

Recommended Layout

This deployment uses:

• Two drives in a mirrored vdev for redundancy
• One large standalone drive for additional storage capacity

Example:

Resulting ZFS pool:

tank
 ├─ mirror-0 (1.9TB + 1.8TB)
 └─ sda      (3.7TB)

This setup gives you:

• Redundancy for important data
• Extra storage capacity
• Expandable architecture
• Snapshot support
• Compression and integrity checking

Ubuntu Server Installation

Start with a clean installation of:

• Ubuntu Server 22.04 LTS or newer

During installation:

• Choose Custom Storage Layout
• Do NOT select the automatic ZFS installer
• Install Ubuntu onto a separate SSD, NVMe, or USB boot device

Once installation finishes:

sudo apt update && sudo apt -y upgrade
sudo reboot

Install ZFS Utilities

Install the ZFS packages:

sudo apt install -y zfsutils-linux

Verify connected drives:

lsblk -o NAME,SIZE,MODEL

Creating the ZFS Pool

⚠️ Warning: The following command erases all data on the target drives.

sudo zpool create \
  -o ashift=12 \
  -o autotrim=on \
  tank \
  mirror /dev/sdb /dev/sdc \
  /dev/sda

Verify the pool:

zpool status
zpool list

Recommended ZFS Settings

These settings improve performance and reduce unnecessary disk activity.

sudo zfs set compression=lz4 tank
sudo zfs set atime=off tank
sudo zfs set xattr=sa tank
sudo zfs set normalization=formD tank

What These Settings Do

Creating Organized Datasets

Datasets make ZFS management much easier.

sudo zfs create tank/data
sudo zfs create tank/backups
sudo zfs create tank/media
sudo zfs create tank/docker

Optional custom mount points:

sudo zfs set mountpoint=/tank/data tank/data
sudo zfs set mountpoint=/tank/backups tank/backups

Enable SMART Disk Monitoring

Install SMART monitoring tools:

sudo apt install -y smartmontools
sudo systemctl enable smartd --now

Test a drive:

sudo smartctl -a /dev/sda

This allows you to monitor disk health and detect failures early.

Schedule Weekly ZFS Scrubs

ZFS scrubs verify data integrity and should run regularly.

Create the scrub script:

sudo nano /usr/local/sbin/zfs-scrub-tank.sh

Add:

#!/bin/bash
/usr/sbin/zpool scrub tank

Make it executable:

sudo chmod +x /usr/local/sbin/zfs-scrub-tank.sh

Edit root cron:

sudo crontab -e

Add this line:

15 0 * * 0 /usr/local/sbin/zfs-scrub-tank.sh

This runs every Sunday at 12:15 AM.

Check scrub status anytime:

zpool status

Installing Webmin

Webmin provides a convenient browser-based administration panel for your Linux server.

Install the repository key:

curl -fsSL https://download.webmin.com/jcameron-key.asc | sudo gpg --dearmor -o /usr/share/keyrings/webmin.gpg

Add the repository:

echo "deb [signed-by=/usr/share/keyrings/webmin.gpg] https://download.webmin.com/download/repository sarge contrib" \
| sudo tee /etc/apt/sources.list.d/webmin.list

Install Webmin:

sudo apt update
sudo apt install -y webmin

Access Webmin:

https://SERVER-IP:10000

Integrating ZFS with Webmin

Install required dependencies:

sudo apt install -y perl libjson-perl

Inside Webmin:

• Navigate to Others → Command Shell
• Run:

zpool status
zfs list

Optional:

• Install the ZFS Filesystems module
• Restart Webmin

Best Practices for ZFS + Webmin

Recommended

• Manage datasets through Webmin
• Monitor disk usage
• Run snapshots
• Review scrub results

Avoid

• Destroying pools from the GUI
• Making vdev-level changes in Webmin

Always use the CLI for advanced ZFS management tasks.

Optional Enhancements

Automatic Snapshots

sudo apt install -y zfs-auto-snapshot

Email Notifications

sudo apt install -y mailutils

Health Checks

zpool status -x

Final Thoughts

This deployment provides a powerful balance between:

• Capacity
• Redundancy
• Flexibility
• Expandability

Using Ubuntu Server, ZFS, and Webmin together creates an enterprise-style storage environment perfect for:

• Homelabs
• Media servers
• Backup systems
• Docker storage
• Virtualization platforms