Chapter 11. Adjust CRUSH Tunables

Red Hat Ceph Storage CRUSH tunables defaults to bobtail, which refers to an older release of Ceph. This setting guarantees older Ceph clusters are compatible with older Linux kernels. However, new Ceph clusters running on RHEL 7 should reset CRUSH tunables to optimal. For example:

ceph osd crush tunables optimal

Please see the Storage Strategies Guide, Chapter 9, Tunables for more details on the CRUSH tunables.