'Remove an existing volume from cinder management.
:param volume: Reference to the volume to be unmanaged.'

def unmanage(self, volume):

    lcfg = self.configuration
    new_name = ('unmanaged-' + volume['name'])
    try:
        self.zfssa.set_lun_props(lcfg.zfssa_pool, lcfg.zfssa_project, volume['name'], name=new_name, schema={'custom:cinder_managed': False})
    except exception.VolumeBackendAPIException:
        with excutils.save_and_reraise_exception():
            LOG.error('Failed    to    rename    volume    %(existing)s    to    %(new)s.    Volume    unmanage    failed.', {'existing': volume['name'], 'new': new_name})
    return None
