Oracle Talks Up Btrfs Rather Than ZFS For Their Unbreakable Enterprise Kernel 6
Unbreakable Enterprise Kernel 6 is making use of the upstream Linux 5.4 kernel and with the more recent kernel code-base the Btrfs driver allows for configurable compression level, other compression improvements, fallocate zero-range support, swapfile support, unregistering scanned devices, out-of-band deduplication, and other features compared to the prior state of Btrfs support on Oracle Linux.
Continued Btrfs support is one of the ways Oracle has been promoting Oracle Linux and their Unbreakable Enterprise Kernel. Oracle along with the likes of SUSE are among the few companies still backing Btrfs while the likes of Red Hat are focused on XFS+Stratis, Ubuntu on EXT4 and ZFS, etc. Oracle formerly employed Chris Mason as the creator of Btrfs.
While Oracle has brought DTrace to their Unbreakable Enterprise Kernel, they haven't embraced ZFS on Linux with either OpenZFS or bringing their official ZFS file-system support to Linux... Oracle could relicense their in-house ZFS code if they so chose in order to make it upstream-acceptable, but to date they have not, and instead are still pushing Btrfs for Linux boxes. ZFS just remains at play with their ongoing Solaris 11.4 releases.
More details on Btrfs with Oracle's Unbreakable Enterprise Kernel 6 via the Oracle Linux blog.