How to use ZFS on root in Ubuntu 19.10

5 min read 06-11-2024

Introduction

ZFS is a powerful, modern, and feature-rich file system that offers a wide range of benefits, including data integrity, efficient storage, and advanced features like snapshots and data deduplication. For those seeking to leverage these advantages on their Ubuntu 19.10 systems, installing ZFS as the root file system can be a compelling choice. This guide provides a comprehensive walkthrough, detailing each step required for a successful ZFS root installation on Ubuntu 19.10.

Prerequisites

Before embarking on this journey, ensure you have the following prerequisites:

Ubuntu 19.10 Installation Media: You will need an Ubuntu 19.10 installation image to create a bootable USB drive.
Sufficient Storage: ZFS requires ample disk space, especially if you plan to leverage its advanced features.
Backup: It is crucial to back up your important data before proceeding. This ensures data recovery if something goes wrong.
Understanding: A basic understanding of command-line interfaces (CLIs) and file system concepts is beneficial, although this guide will strive to provide clear instructions.

Step 1: Download and Install ZFS

The first step is to acquire and install the necessary ZFS packages. Ubuntu 19.10 offers a convenient way to achieve this through its official repositories:

Update package lists: Begin by updating your package lists to reflect the most recent software available.
```
sudo apt update 
```
Install ZFS: Next, install the ZFS packages.
```
sudo apt install zfs
```
Verify Installation: After installation, confirm that ZFS is installed correctly.
```
zfs
```
If the command executes without errors, you have successfully installed ZFS.

Step 2: Create a ZFS Pool

To store data using ZFS, you need to create a pool. A pool is a collection of storage devices that ZFS combines into a single, unified storage space. Let's create a simple ZFS pool using a single disk.

Identify Disk: Before creating a pool, identify the disk you want to use. Use lsblk command to list all block devices:
```
lsblk
```
Format Disk: Format the disk using the zpool command with the -f flag to force formatting. Replace /dev/sdX with the actual device name identified in the lsblk output.
```
sudo zpool create -f mypool /dev/sdX
```
Verify Pool: After creating the pool, verify its existence using the zpool list command:
```
zpool list
```
You should see the newly created pool listed in the output.

Step 3: Configure ZFS Boot Environment (BE)

Now, prepare ZFS to be used as your root file system. This involves creating a dedicated boot environment.

Create a ZFS Boot Environment: Create a new boot environment using the zfs command.
```
sudo zfs create -b -s mypool/BOOT-A 
```
Mount Boot Environment: Mount the newly created boot environment to a temporary directory.
```
sudo mount -t zfs mypool/BOOT-A /mnt
```

Step 4: Install Ubuntu 19.10 with ZFS

Now, install Ubuntu 19.10 with ZFS as the root file system. This process requires some additional steps during the Ubuntu installation process:

Boot from Installation Media: Boot your system from the Ubuntu 19.10 installation media.
Select Language and Keyboard: Choose your preferred language and keyboard layout.
Select "Install Ubuntu": Proceed to the installation screen.
Choose "Something Else": Select the "Something Else" option to customize the installation.
Create a New Partition Table: Select the disk on which you created the ZFS pool and create a new partition table.
Create a Root Partition: Create a new primary partition for the root file system.
Format as ZFS: Use the "Format" option and select the "ZFS" file system.
Mount Point: Specify / as the mount point for the root partition.
Choose ZFS Boot Environment: Select the ZFS boot environment you created (e.g., mypool/BOOT-A) as the boot device.
Install Ubuntu: Continue with the remaining installation steps.
Reboot: Once the installation is complete, reboot your system.

Step 5: Set ZFS Boot Environment as Default

After booting, configure the newly created ZFS boot environment as the default.

Install ZFS Boot Tools: Install the necessary ZFS boot tools:
```
sudo apt install zfs-boot-tools
```
Set Default Boot Environment: Set the newly created ZFS boot environment as the default.
```
sudo zfs set bootfs=on mypool/BOOT-A
```
Reboot System: Reboot your system to load the new boot environment.

Step 6: Configure GRUB

Once the system boots into the ZFS boot environment, configure GRUB to ensure it recognizes the ZFS root file system.

Update GRUB: Update GRUB to reflect the new ZFS boot environment.
```
sudo update-grub
```
Verify Boot Entries: Verify that the GRUB menu shows the ZFS boot entry correctly.

Step 7: Enjoy ZFS on Root

Congratulations! You have successfully installed Ubuntu 19.10 with ZFS as your root file system. Now, you can leverage ZFS's benefits, including:

Data Integrity: ZFS provides strong data integrity guarantees, ensuring the reliability of your data.
Snapshotting: Create snapshots of your entire system to revert to previous states easily.
Deduplication: ZFS can deduplicate data, saving storage space by storing only unique data blocks.
Compression: ZFS can compress data, reducing the amount of storage space required.

Troubleshooting

Should you encounter any issues during installation, remember these troubleshooting tips:

Check Log Files: Consult system logs for error messages. The messages can provide valuable clues for debugging.
Verify Disk Connections: Ensure that the disk used for the ZFS pool is securely connected.
Check ZFS Pool Status: Use zpool status to check the health of the ZFS pool.
Seek Online Resources: Many resources, including the official ZFS documentation, can help you troubleshoot specific problems.

Conclusion

By following these steps, you can successfully install Ubuntu 19.10 with ZFS as your root file system, harnessing its powerful features. ZFS offers a robust and feature-rich storage solution that can significantly enhance the reliability, efficiency, and management of your Ubuntu system. Remember to back up your data before making any changes, and leverage online resources if you encounter any issues.

FAQs

Q: What are the advantages of using ZFS as the root file system?

A: Using ZFS as the root file system offers several advantages, including:

Data Integrity: ZFS provides strong data integrity, ensuring that your data is protected from corruption.
Snapshotting: ZFS allows you to create snapshots of your entire system, allowing you to easily revert to previous states.
Deduplication and Compression: ZFS can deduplicate and compress data, saving disk space and reducing storage requirements.
Advanced Features: ZFS offers other advanced features like data scrubbing, automatic repair, and more.

Q: Can I use ZFS on other Linux distributions?

A: Yes, ZFS is available on other Linux distributions, including Fedora, Debian, and openSUSE.

Q: What if I need to install ZFS on a system without an internet connection?

A: You can install ZFS packages from a local mirror or CD-ROM. Consult the ZFS documentation for detailed instructions.

Q: How do I create multiple ZFS pools?

A: To create multiple ZFS pools, simply repeat the steps outlined in the guide, specifying a different name and disk for each pool.

Q: Can I migrate my existing Ubuntu system to ZFS?

A: While migrating an existing Ubuntu system to ZFS is possible, it's a more complex process. You may need to use specialized tools and follow specific procedures.

Q: What are the performance implications of using ZFS on root?

A: ZFS performance can vary depending on factors like hardware, pool configuration, and workload. However, ZFS is generally known for its efficiency and scalability.