* The meaning of 'osd scrub max interval' has been changed: it is now
  the amount of time after which a PG will be scrubbed regardless of
  the system load.  The option 'osd scrub min interval' now has the
  previous meaning: the amount of time before a PG is scrubbed if the
  load is low.  The defaults have been adjusted such that the only
  change in behavior is that PGs will now be scrubbed after a week
  even if the system load remains high.  However, if either of these
  options have been changed in ceph.conf, those settings should be
  reviewed in light of their adjusted meanings.

* The 'ceph osd pool delete <poolname>' and 'rados rmpool <poolname>'
  now have safety interlocks with loud warnings that make you confirm
  pool removal.  Any scripts curenty rely on these functions zapping
  data without confirmation need to be adjusted accordingly.

* ceph-mon now requires the creation of its data directory prior to
  --mkfs, similarly to what happens on ceph-osd.  This directory is
  no longer automatically created, and custom scripts should be
  adjusted to reflect just that.