Comment 1 for bug 1267104

This is referring to the fact that you must pass a "--size" argument for the volume.

The reason why the size argument isn't marked as required in the python-troveclient is that volume-support can be toggled off in Trove via https://github.com/openstack/trove/blob/master/etc/trove/trove.conf.sample#L54.

The message is confusing however, considering it's referring to a 'volume property', when the argument in the cli is 'size' not 'volume'.