Storage Modes in SSAS (MOLAP, ROLAP and HOLAP)

There are three standard storage modes (MOLAP, ROLAP and HOLAP) in OLAP applications which affect the performance of OLAP queries and cube processing, storage requirements and also determine storage locations.

SSAS (2005 and 2008) supports not only these three standard storage modes but supports proactive caching, a new feature with SSAS 2005 which enables you to combine the best of both worlds (ROLAP and MOLAP storage) for both frequency of data refresh and OLAP query performance.

In the part 1 of this article, I will start my discussion with an overview of each mode and then in part 2 I will cover the new proactive-caching feature of SSAS.