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With Btrfs file system gone in RHEL 8, look at alternatives

In the XFS, Ext4, Btrfs and ZFS comparison, Linux users will say goodbye to Btrfs in RHEL 8. Learn more about your options and what can fill the gaps once development halts.

When it was first launched in 2009, the Btrfs file system had a promising future. Many expected Btrfs to replace ZFS, a file system that hadn't made it into the Linux operating system for legal reasons, and Linux distributions started working on a Btrfs implementation.

But with the release of Red Hat Enterprise Linux (RHEL) 7.4, Red Hat announced it will stop further developments on Btrfs. It will still be an option in further releases of RHEL 7, but it will be discontinued in RHEL 8, which is expected sometime in 2018.

Although the Red Hat announcement will leave customers wondering about the fate of Btrfs, it doesn't mean that Btrfs file system developments have come to a standstill. Btrfs is still an important file system that major companies, including Facebook, Fujitsu, Oracle and SUSE, continue to use and actively develop. Compare that to the competing XFS file system that Red Hat, SUSE and other independent contributors are currently developing, and it becomes clear that the Btrfs community is far from inactive.

Alternatives to Btrfs file system

However, the legal status of [ZFS] isn't clear, so neither Red Hat nor SUSE will ever consider using it in their distributions.

Companies such as Canonical considered the ZFS file system for Linux distributions, which is actively used in Berkeley Software Distribution environments. However, the legal status of this file system isn't clear, so neither Red Hat nor SUSE will ever consider using it in their distributions.

With that, only XFS and Ext4 remain as valid alternatives to the Btrfs file system. XFS introduced Copy-on-Write (COW) -- one of Btrfs's main features -- in 2016, and made it a strong alternative to Btrfs. However, XFS doesn't deal well with many small files, such as on mail-server workloads. Btrfs, on the other hand, stores small files with metadata in the database, which gives small files as much accessibility as larger files.

Potential Btrfs file system drawbacks

Some say that Btrfs is an unreliable or unstable file system. However, this assertion seems to be unfair for more current releases. Btrfs doesn't have the fsck utility -- not because it can't check the file system, but because Btrfs uses a different approach to repair the system.

The file system uses back references and COW technology. COW technology ensures that new blocks will never overwrite old blocks, which drastically reduces the chances for failure. The back references require every inode to point back to the root directory, which makes it easier to repair. If something does go wrong with the Btrfs file system, it has a powerful repair function that an admin can start directly from the Btrfs command-line interface.

Part of the reason behind Btrfs's poor reputation is also due to the large number of new features in the file system. Obviously, new features are still in development and, for that reason, they're often not stable enough to use. However, the main distributions that use Btrfs only include its stable features.

The life of the Btrfs file system is far from over. Red Hat's abandonment of Btrfs just means that the company has taken a different route, but the development shouldn't have major consequences when using Btrfs in other environments.

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