To prepare your BW system to migrate to HANA, it’s important to estimate the memory size of the new HANA server. For BW 7.3 customers with a sufficient ST-PI Patch level, the BW HANA Sizing report /SDF/HANA_BW_SIZING should already be in the system. This sizing report helps customer to estimate the memory requirement of their BW system after migrating to HANA.
The following BW system currently runs on SQL 2016 with 1.6 Terabyte database size.
To estimate the size of the future HANA based system, execute the report /SDF/HANA_BW_SIZING in SE38:
The ‘Low’ precision option should already give a rather comprehensive estimate of the future HANA size.
The report completed running in about 2 hours, and it outputs a file with details of your future recommended HANA system settings. The first 3 sessions are of particular importance:
Source DB Contents
This section shows current statistics: Of the 1.4 Tb in the current SQL database:
- 105Gb will be converted to HANA row tables
- 379Gb will be converted to HANA column tables
- 972Gb will be excluded in HANA, e.g. BW aggregates which no longer needed in HANA
Minimum Size Recommendations
This section shows recommendation from SAP for the new HANA system. The above figure shows that a minimum of 512Gb physical memory is needed for the new server, with a recommended configuration of 1024Gb. The actual requirement of the system is 441Gb. Compare to the current system (1.4Tb), the compression factor is from 3 to 4.
This section further break down the 441Gb minimum requirements into row store and column store, and reserves for caches. With a 1Tb system, the utilization rate is 45% which means future growth is also possible with a 1Tb configuration.