Comment 6 for bug 1713032

I got a failed bootstrap with a quick test - journalctl -xe -u ceph-mon revealed:

Oct 20 13:36:07 juju-e856f0-0 ceph-mon[13887]: error: monitor data filesystem reached concerning levels of available storage space (avail
Oct 20 13:36:07 juju-e856f0-0 ceph-mon[13887]: you may adjust 'mon data avail crit' to a lower value to make this go away (default: 5%)
Oct 20 13:36:07 juju-e856f0-0 systemd[1]: ceph-mon.service: Main process exited, code=exited, status=28/n/a
Oct 20 13:36:07 juju-e856f0-0 systemd[1]: ceph-mon.service: Unit entered failed state.
Oct 20 13:36:07 juju-e856f0-0 systemd[1]: ceph-mon.service: Failed with result 'exit-code'.
Oct 20 13:36:37 juju-e856f0-0 systemd[1]: ceph-mon.service: Service hold-off time over, scheduling restart.
Oct 20 13:36:37 juju-e856f0-0 systemd[1]: Stopped Ceph cluster monitor daemon.

Might be the same issue I guess?