Understanding Persistent Memory allocation based on HDB_SIZING report

[cosmo83]

Dear SAP folks,

We are trying to move our existing HANA infrastructure based on S4HANA 1610, from one provider to another. We would like to ideally take advantage of the persistent memory available on the newer hardware in the market.

There is a lot of confusion, on selecting the proper PMEM ratio for the operations.

Iam just doing a further dig deep into memory sizing.

If you are looking at the report for PMEM

From the study i have done till now and from the report, it shows that the Column Store Data is a good fit for persistent memory, and from the report also, the value looks good. Now the confusion starts at the PMEM ratio.

As per the report (Since Workspace is nothing but Row + Store Data), at the best i can have is 1:1 ratio of DRAM to PMEM. If the idea is to have at the best 1:1 ratio, why is SAP saying 1:2 , 1:4 ratios are also available.

Regards

Phani

[sumitjais]

Hi Phani,

Just trying to understand your confusion.

"As per the report (Since Workspace is nothing but Row + Store Data), at the best i can have is 1:1 ratio of DRAM to PMEM. If the idea is to have at the best 1:1 ratio, why is SAP saying 1:2 , 1:4 ratios are also available"

Could you please suggest the reference where SAP says the ratio for DRAM : PMEM?

The note 2700084 - FAQ: SAP HANA Persistent Memory clearly states - " The share of persistent memory and DRAM depends on the amount of column store main storage data that exists in the system."