Why POWER8 Is Sometimes The Best Platform To Run SAP HANA
November 23, 2020 Timothy Prickett Morgan
It is a truth in this world that you get what you pay for, and it is absolutely true for the systems that companies buy to support SAP’s HANA in-memory database and their applications for data warehousing and online transaction processing.
It is no secret to the Power Systems faithful that IBM’s Power architecture has consistently offered reliability, availability, and serviceability features in both the processor and the system architecture that are superior to X86 alternatives. And the Power Systems platform also offers superior compute, memory, and I/O capacity and bandwidth benefits on top of that, which absolutely justifies the premium price that Big Blue charges compared to commodity X86 iron.
Now here is the fun bit: You can pay a lot less for a cluster of certified pre-owned POWER8 machinery to run data warehouses based on SAP HANA than is possible for so-called “commodity” X86 servers of equal performance, and sometimes beat the very substantial price/performance advantage that POWER9 machinery has over X86 setups. So there are two ways in which Power Systems iron can beat X86 iron, and for those companies who are conscious about their budgets, but who nonetheless want to get modern with SAP HANA in-memory databases for either data warehousing or transaction processing, then POWER8 represents both a safe and affordable option.
The big reason this is true is that the Power Systems servers based on POWER8 chips are absolutely modern in every sense of the word relative to the current crop of Xeon SP X86 chips from Intel and their Epyc alternatives from AMD.
IBM and SAP first started talking about bringing the HANA in-memory database to Power Systems back in the summer of 2014, and less than a year later the two had worked together to certify HANA to run on the SUSE Linux Enterprise Server atop the PowerVM hypervisor on POWER8 machines. We outlined IBM’s aspirations for SAP HANA on Power iron several years later as the first POWER9 machines came to market, and even then IBM was telling customers and resellers that it was perfectly reasonable to use a POWER8 machine while the high-end POWER9 machines had not yet come to market, and we have talked specifically how IBM’s aggressive support for SAP HANA on Power Systems has kept the Power Systems platform strong, particularly on midrange and high-end machinery that has significant scalability compared to X86 alternatives. Suffice it to say, SAP HANA needs platforms like POWER8 and POWER9 systems, and IBM needs for customers to embrace POWER8 and POWER9 systems for running HANA – and SAP needs it, too, for all the same technical and economic reasons because anything that helps HANA deliver better value and uptime makes both IBM and SAP successful for their customers.
With certified pre-owned POWER8 systems selling for around 20 percent of list, and many of their components also being available for comparably low prices, customers can save a considerable amount of money deploying SAP HANA on POWER8 machines and get many of the benefits of POWER9 machinery and – this is the important part – have features that are still not available on X86 platforms.
There are a lot of benefits that come with POWER8 systems with regard to SAP HANA, but it is probably a good idea to list some of the important ones:
With SAP HANA being an in-memory system, obviously memory capacity, memory bandwidth, and memory resilience are vital. And so is I/O between memory subsystems and flash storage systems, which are the means by which HANA is backed up for quick recovery in the unlikely case of a glitch in a system or the HANA software stack. Perhaps most importantly, memory scalability is very important particularly for SAP HANA systems because the use of the system and therefore the underlying database can grow very quickly, so it is important to have some breathing room for memory capacity and bandwidth.
The POWER8 processor, like the POWER9 processor, has eight DDR4 memory channels compared to only six memory channels for the past several generations – and current “Cascade Lake” and “Cooper Lake” Xeon SP processors are still limited to six memory controllers and therefore IBM has a 33 percent memory capacity and bandwidth advantage on like-for-like memory speeds. And while Intel is trying to stretch memory capacity with Optane persistent memory, there is no way to improve the memory bandwidth and the performance is substantially lower than for real DDR4 memory.
The POWER8 machines also incorporate IBM’s chipkill error correction, which debuted with POWER7 processors back in 2010, and POWER8 added memory bus lane sparing as a hardware “self-healing” feature to get around errors. POWER8 memory also has an extra chip per rank on the memory modules so they can recover from chip failures in the field.
Perhaps equally importantly, SAP HANA is virtualized on POWER8 and POWER9 machines, rather than running on bare metal as is often the case with X86 servers, and the PowerVM hypervisor can dynamically optimize and manage the processor, the memory, and the I/O resources in the system. PowerVM is built into the Power Systems server and runs by default for all workloads; it is not an afterthought, as is the case with VMware’s ESXi and vSphere stack, or Microsoft’s Hyper-V stack, or even Red Hat’s Enterprise Virtualization KVM stack on X86 iron. With PowerVM supporting SAP HANA, multiple partitions comprising a kind of virtual cluster within a single big NUMA machine to run a HANA data warehouse (or a portion of one). IBM’s POWER8 servers can support up to eight HANA partitions per machine, and CPU cores and memory can be dynamically moved across partitions as needed on such machines. Moreover, with physically clustered setups, Live Partition Mobility features inherent in the Power Systems platform can be used to move logical partitions from one physical machine to another to allow for upgrades to be performed on machines without downtime. Finally, the use of PowerVM to create virtual SAP HANA clusters on a single machine or across a handful for machines can help drive up the utilization across the Power processors – and do so in a way that is not easily accomplished on X86 servers because of the compute, memory, and I/O limits of X86 iron.
There are a lot of elements that go into the cost of an SAP HANA environment, but software is an important one that cannot be overlooked when considering the complete HANA platform. While SAP HANA licenses are priced on a per-customer enterprise license, much of the adjunct software that supports HANA and its applications, including operating system licenses and other middleware, are often priced on a per-core basis and can be less expensive across a HANA environment because it takes far fewer Power cores to support any given workload than it does an X86 environment. And that leads to lower power, cooling, and other operational costs as well fewer Power Systems boxes needed to support a given HANA workload.
When you add this all up, there are significant return on investment and total cost of ownership benefits that accrue to Power Systems running SAP HANA compared to running the in-memory database and its applications on standalone or clustered X86 systems. Forrester Research did a “total economic impact” study of running SAP HANA on Power Systems, and found that a particular HANA workload could run on three Power Systems machines based on POWER9 iron instead of 20 X86 servers, with the following results:
The significant benefit of the POWER9 setup that Forrester reviewed was not just the substantially lower cost of the POWER9 systems to run SAP HANA, but also the avoidance of four hours of planned and unplanned downtime per month that was experienced on the X86 cluster running SAP HANA. And the load on system administrators on the POWER9 setup was also 60 percent lower in terms of babysitting the X86 iron.
Now, here is the important thing: The case for certified pre-owned POWER8 systems is even better and the return on investment is faster and total economic impact higher than it was for POWER9 systems.
IBM’s Global Asset Recovery Services division, which is reselling POWER8 machinery on behalf of IBM, has created its own comparison for running SAP HANA on POWER8 machines with PowerVM in contrast with running it on X86 machinery running Linux and VMware ESXi/vSphere. Take a look:
In the comparison above, the people at Global Asset Recovery Services did their best to take a collection of X86 and POWER8 machines end up with roughly the same compute performance, memory capacity, and usable SAN storage as a backup for the SAP HANA clusters. In this case, there were four Power E850 four-socket servers backed by a Storwize V7000 SAN pitted against fourteen ProLiant X86 servers from Hewlett Packard Enterprise backed by a 3PAR SAN.
Here is how the three-year total cost of ownership costs stacked up, new HPE X86 versus certified pre-owned POWER8:
There are savings across the board, but obviously the biggest savings come from the substantially lowered cost of the server infrastructure. The chart above does not take into account reduced downtime or other factors that would go into a total economic impact analysis, but it does show a 62 percent lower TCO for the POWER8 setup compared to the X86 setup.
If cash is king right now – and it clearly is for most midrange and enterprise shops these days – then customers have to think really hard about buying X86 iron to run SAP HANA, and they also have to give serious consideration to a certified pre-owned POWER8 setup, too. Check out the POWER8 pricing on IBM’s Certified Pre-Owned Owned Marketplace.
This content is sponsored by IBM.
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