Code review comment for lp:~axwalk/charms/trusty/ceph/trunk

I've fixed the proof error (proof is stricter than necessary, but follows the docs), and added an optional osd-journal store. This is currently handled the same as the existing config: one-shot, at deployment time only. Storage charmers will need to update it to handle dynamic journal changes if that's ever a requirement.

I've put up another MP to charm-helpers to fix the optional parameters inconsistency, and will update this when it's merged.