Data managed by the SAP BW application can be classified into 3 basic categories:
Hot – high-frequent access (planning, reporting, advanced analytics, data manipulations)
Warm – less frequent access, relaxed performance SLAs (usually batch jobs), simple access patterns
Cold – archive, data lakes
For the “warm” data in your BW system SAP HANA offers currently 2 options: the non-active data concept (high-priority RAM displacement) and HANA dynamic tiering (using an ExtendedStorage server). We have evaluated the situation anew and have seen that with the advancements in hardware technology and in SAP HANA we do now have an even simpler and more intriguing option. Instead of introducing a new ExtendedStorage server into your HANA cluster to store the “warm” data you can use standard HANA nodes but with a different sizing formula and RAM/CPU ratio instead.
You basically run an “asymmetric” HANA scale-out landscape: a group of nodes (for your “hot” data) with standard sizing and another group with a “relaxed sizing” (you basically store more of the “warm” data on these nodes than RAM is available – the “extension” group). This allows you to run a HANA scale-out landscape with fewer nodes and less overall RAM but with the same data footprint.
Such a setup can be significantly easier to set up and administrate and it offers, right out of the box, all features of HANA with respect to operations, updates, and data management. The differentiation of data into “hot” and “warm” can be done easily via the BW application and using the standard HANA techniques to re-locate the data between nodes.
We are currently preparing the boundary conditions for these setups and are in intensive discussion with our hardware partners to enable attractive offers. The goal is to start a beta program in mid-2016. Please stay tuned for more details to follow very soon.
Please note that this setup is currently only planned for BW-on-HANA since it heavily relies on BWs partitioning, pruning and control of the access patterns. For applications looking for a more generic “warm” data concept, the HANA dynamic tiering feature is still a valid option. HANA dynamic tiering continues to be supported for BW as well.