anchor.diff:          %% LUMA API Key, must be identical with API Key in external LUMA
           %% service.
           lumaApiKey => {string, optional},
  -        %% The type of storage.
  -        type => {equal, <<"nulldevice">>},
           %% Minimum latency in milliseconds, which should be simulated for
           %% selected operations.
           latencyMin => {integer, optional},
  
positive.code:         %% LUMA API Key, must be identical with API Key in external LUMA
          %% service.
          lumaApiKey => {string, optional},
          %% The type of storage.
          type => {equal, <<"ceph">>},
          %% The username of the Ceph cluster administrator.
          username => string,
          %% The admin key to access the Ceph cluster.
  
negative.code:         %% LUMA API Key, must be identical with API Key in external LUMA
          %% service.
          lumaApiKey => {string, optional},
          %% The username of the Ceph cluster administrator.
          username => string,
          %% The admin key to access the Ceph cluster.
  