The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.
If the root partition is formatted using
btrfs, the system is unable to boot into
the Red Hat Compatible Kernel. This is because the features
included in the version of btrfs provided,
are not supported on older kernel versions.
btrfs is included only as a technology
preview for the Red Hat Compatible Kernel and is not fully
supported on this kernel.
btrfs is fully supported in production with
the Unbreakable Enterprise Kernel. Systems booting into this
kernel are unaffected by the issue.
Users must be aware when formatting file systems from the
installation ISO, that formatting the root partition with
btrfs makes it impossible to boot into the
Red Hat Compatible Kernel. Note that btrfs
is the default file system for system disks when using the
boot-uek.iso. If you are installing from
this ISO and you intend to use the RHCK, you must change the
default system disk layout in the installer.
(Bug ID 23198167)