Comparing PMEM Options

Persistent Memory (PMEM) is an exciting technology addressing an on-going weak-link in computer architecture which is the volatility of main memory. Persistent memory has the opportunity to dramatically change how systems are architected for resiliency. This is especially important for SAP HANA workloads which rely on the in-memory database with the same name; HANA. Having persistence in main memory allows the data persistence layer to move from main storage to main memory.

Intel-based x86 systems and IBM POWER9 offer a PMEM solution; with obvious similarities and differences. Intel's solution is Optane DC Persistent Memory (i.e. DCPMM) while IBM's solution is virtual Persistent Memory (i.e. vPMEM). This article will highlight these similarities and differences. Solution Architects, whether it is the client, business partner or manufacturer will need to pay strict attention to detail ensuring the desired solution delivers the capabilities to meet business requirements.

The following tables list every item to consider for any Intel solution. It will be immediately obvious the extensive number of items required to check for Intel DCPMM based solutions. When architecting and deploying an Intel solution, it requires ~57 steps, which is approximately 8X more than what is needed with IBM's vPMEM offering. The steps shown are what is needed to prepare the hardware for an OS, meaning there will be additional steps to configure the PMEM for use by an OS and application.

It should also be noted the first list was created primarily using Lenovo documentation. Though these list items are not unique to Lenovo, all of the major Intel manufacturers have similar requirements listed in their documentation. Kudos to Lenovo for having very detailed and clear documentation.

Intel Optane DC Persistent Memory

The following list is for IBM POWER9 shows what is needed to ensure a proper solution. This list is obviously much less than Intel's list. It would be reasonable to question the fairness of these two lists. To question my partiality, to favor one over the other. My preferences though played no role as I let the manufacturer's documentation speak for itself.

IBM POWER9 vPMEM

The items in the following list which are not enumerated are intended to provide answers to questions that I believe would arise out of a comparison to the Intel list above.

Note: If you have questions on what was intended by an item in either list or if you have suggestions to improve, correct or clarify content in this article, please send me a message.

Summary

There is no other way to say it other than to state the obvious. Intel's Optane DCPMM checklist ensuring proper design and architecture is onerous. There is more to compare and discuss regarding each solution not to mention recognizing the difference between truth vs marketing hype. Intel is a bolt-on solution relying on non-DRAM-based memory which allows multiple configurations further increasing the potential for an unsatisfactory and underperforming solution. Contrast that to IBM POWER9 which merely enables PMEM functionality to its standard DRAM memory. This ensures no compromise in performance, flexibility, and resiliency regarding the memory subsystem.

References

1. https://lenovopress.com/lp1066-intel-optane-dc-persistent-memory#implementation-requirements
2. https://lenovopress.com/lp1066-intel-optane-dc-persistent-memory
3. Lenovo Configuring DC Persistent Memory Module (DCPMM) https://thinksystem.lenovofiles.comCon/help/index.jsp?topic=%2F7X01%2FDCPMM_configuration.html
4. IBM Planning & Implementation Guide https://www-03.ibm.com/support/techdocs/atsmastr.nsf/002573f7000ac64286256c71006d2e0a/c32b40501f4f76c886257de0004fa1d4/$FILE/vPMEM-SAPHANA-Whitepaper-Draft-V0.1.pdf
5. SAP blog by Dennis Padia https://blogs.sap.com/2020/01/24/sap-hana-of-persistent-memory-using-intels-dcpm-or-ibms-vpmem/
6. SAP blog by Denys van Kempen https://blogs.sap.com/2020/01/11/sap-hana-on-ibm-power-systems/

Learn More

Send me a message to schedule a meeting to learn how these Persistent Memory offerings stack up for your proposed SAP HANA environment. We can also make this a topic in up a no-cost SAP HANA Readiness Workshop. To learn more about hosting a workshop or for general questions about our SAP practice, please visit Clear Technologies SAP Practice. To learn about our core business offerings, visit Clear Technologies, Visual Storage Intelligence, and the AI practice; Clear Intelligence.

About the author: Brett Murphy is a Client Executive and Executive Architect at Clear Technologies. With over 25 years of industry experience working with Enterprise solutions, Brett is an IBM Champion specializing in SAP and SAP HANA environments. Follow on twitter @PowerMan4EVR and blog https://powertheenterprise.wordpress.com.