Currently we don't have any way to let the user know the size of hot and cold tier. Without this the watermark testing and usage of this feature will be really difficult. We got to have to let the end user/admin know the sizes of hot and cold tier, by may be displaying in volinfo or any other way. Using mount point , admin can find only the size of volume and not that of the tier.
This is a good idea for additional output but may be deferred to when we have time.