The distinction between warm, hot, and very hot data is conceptual and only loosely parallel to the WARM and HOT categories of temperature-based block-level compression. Very Hot data is data that you determine is to be added to the Very Hot cache or that is contained on Very Hot cylinders.
Warm and hot data typically constitute what is often called the operational data store.
Hot and warm data are both important in the extended lifetime of data, particularly with respect to multivalue compression (see Compression Types Supported by Vantage), as is cool data to a lesser degree.