This does not appear to specific to arm64. On an x86 internal dev cloud, Trusty-Mitaka, I also have to reboot my nova instance after attaching ceph-backed cinder volumes before they are usable.
Next steps: test again with vanilla cinder (not ceph-backed).
Ryan Beisner (1chb1n) wrote on 2017-01-26:
This does not appear to specific to arm64. On an x86 internal dev cloud, Trusty-Mitaka, I also have to reboot my nova instance after attaching ceph-backed cinder volumes before they are usable.
Next steps: test again with vanilla cinder (not ceph-backed).