SAPonPower

An ongoing discussion about SAP infrastructure

Oracle publishes another SAP benchmark result with limited value

About a month ago, I posted a review of Oracle’s SAP ATO benchmark result and pointed out that ATO is so obscure and has so few results, that other than marketing value, their result was completely irrelevant.  About two weeks later, they published a result on another rarely used SAP benchmark, Sales and Distribution-Parallel.  While there have been a few more publishes on this variety of SD than with the ATO benchmark, the number of publishes prior to this one over the past two years could be counted on one hand, all by Oracle/Sun.

This benchmark is not completely irrelevant, just without context and competitors, it says very little about the performance of systems for SAP.  As the name implies, it requires the use of a parallel database.  While some customers have implemented SAP with a parallel database like Oracle RAC, these customers represent a very small minority, reportedly less than 1% of all SAP customers.  The reason has been discussed in my post on Exadata for SAP, so I will only summarize it here.  SAP is RAC enabled, not RAC aware meaning that tuning and scalability can be a real challenge and not for the faint of heart.  While a good solution for very high availability, the benefit depends on how often you think that you will avoid a 20 minute or so outage.   Some non-IBM customers predict their DB server will only fail every 2 years meaning RAC may help avoid 10 minutes of downtime per year for those customers.  Obviously, if the predicted failure rate is higher or the time for recovery is longer, the benefits of RAC can increase proportionately and if failures occur less often, then the value decreases.

But that is not why this benchmark is of little value.  In reality, the SD benchmark is approximately 1/16 DB workload, the rest being app servers and CI.  To put that in context, for this benchmark, at 1/16 of the total, the DB workload would be approximately 46,265 SAPS.  A 16-core Power 730 has a single system result higher than that as do just about all Westmere-EX systems.  In other words, for scalability purposes, this workload simply does not justify the need for a parallel database.  In addition, the SD benchmark requires that the app servers run on the same OS as the DB server, but since this is SD-Parallel, app servers must run on each node in the cluster.  This turns out to be perfect for benchmark optimization.   Each group of users assigned to an app server is uniquely associated with the DB node on the same server.  The data that they utilize is also loaded into the local memory of that same server and virtually no cross–talk, i.e. remote memory accesses, occurs.  These types of clustered results inevitably show near-linear scalability.  As most people know, near-linear scalability is not really possible within an SMP much less across a cluster.  This means that high apparent scalability in this benchmark is mostly a work of fiction.

Before I am accused of hypocrisy, I should mention that IBM also published results on the SD-parallel benchmark back in early 2008.  Back then, the largest single image SD result achieved 30,000 users @ 152,530 SAPS by HP on the 128 core Superdome of that era.  While a large number, there were customers that already had larger SAP ERP instances than this.  So, when IBM proved that it could achieve a higher number, 37,040 users @ 187,450 SAPS with a 5-node cluster with a total of only 80 cores, this was an interesting proof point especially since we also published a 64-core single image result of 35,400 users @ 177,950 SAPS using the Power 595 within a few days.  In other words, IBM did not try to prove that the only way to achieve high results was using a cluster, but that a cluster could produce comparable results with a few more cores.  In other words, the published result was not a substitute for providing real, substantial results, but in addition to those as a proof of support of Oracle and Oracle RAC.   The last time that Oracle or Sun provided a single image SD result was way back in December, 2009, almost ancient history in the computer world.

This new result, 134,080 users @ 740,250 SAPS on a cluster of 6 Sun Fire x4800 systems, each with 80 Intel Xeon cores is a very high result, but only surpasses the previous high water result on any version of the SD benchmark by 6% while requiring 87.5% more cores.  We can debate whether any customer would be willing to run a 6-node RAC cluster for OLTP.  We can also debate how many customers … in the entire world, have single instance requirements anywhere close to this level.  A typical SAP customer might have 1,000 to 5,000 named users but far fewer concurrent users.  This benchmark does nothing to help inform those customers about the performance they could expect using Oracle systems.

So, this new parallel result neither demonstrates true parallel scalability nor single system scalability or even relevance for small to even very large SAP workloads.  In other words, what value does it provide to the evaluators of technology?   Nothing!  What value does it provide to Oracle?  Plenty!  Not only do they get to beat their chest about another “leadership” result, but they get to imply that customers can actually achieve these sorts of results with this and various other untested and unproven configurations.  More importantly, if customers were actually to buy into RAC as being the right answer for scalability, Oracle would get to harvest untold millions of dollars in license and maintenance revenues.  This configuration included 480 cores meaning customers not utilizing an OEM license through SAP, would have to pay, 480 x .5 (core license factor) x ($47,500 (Oracle license cost) + $22,500 (Oracle RAC license cost)) = $16.8M @ list for the Oracle licenses and another $18.5M for 5 years of maintenance and this is assuming no Oracle tools such as Partitioning, Advanced Compression, Diagnostic Pack, Tuning Pack, Change Management Pack or Active Data Guard.

For comparison, the largest single image system result for IBM Power 795, mentioned above, achieved  just 6% few users with DB2 on a 256 core system.  A 256-core license of DB2 would cost a customer, 256 x (120 PVU) x ($405/PVU) = $12.4M @ list for the DB2 licenses and another $10.9M for 4 years of maintenance (first year of maintenance is included as warranty as opposed to Oracle which charges for the first year of maintenance.)  So, the DB2 license would not be inexpensive, total of $23.3M over 5 years, but that is quite a bit better than the $35.5M for the Oracle licenses mentioned above.

Full results are available at: http://www.sap.com/solutions/benchmark/index.epx

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October 4, 2011 - Posted by | Uncategorized | , , , , , ,

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