system config
1.add sys-cluster/ceph to package.accept_keywords
file:/etc/portage/package.accept_keywords/ceph
sys-cluster/ceph
2. kernel config
Device Drivers --->
Block devices --->
Rados block device (RBD)
File systems --->
Network File Systems --->
Ceph distributed file system
install ceph
3. install ceph
emerge sys-cluster/ceph