SAPonPower

An ongoing discussion about SAP infrastructure

Update – SAP HANA support for VMware, IBM Power Systems and new customer testimonials

The week before Sapphire, SAP unveiled a number of significant enhancements.  VMware 6.0 is now supported for a production VM (notice the lack of a plural); more on that below.  Hybris Commerce, a number of apps surrounding SoH and S/4HANA is now supported on IBM Power Systems.  Yes, you read that right.  The Holy Grail of SAP, S/4 or more specifically, 1511 FPS 02, is now supported on HoP.  Details, as always, can be found in SAP note:   2218464 – Supported products when running SAP HANA on IBM Power Systems .   The importance of this announcement, or should I say non-announcement as you had to be watching the above SAP note as I do on almost a daily basis because it changes so often, was the only place where this was mentioned.  This is not a dig at SAP as this is their characteristic way of releasing updates on availability to previously suggested intentions and is consistent as this was how they non-announced VMware 6.0 support as well.  Hasso Plattner, various SAP executives and employees, in Sapphire keynotes and other sessions, mentioned support for IBM Power Systems in almost a nonchalant manner, clearly demonstrating that HANA on Power has moved from being a niche product to mainstream.

Also, of note, Pfizer delivered an ASUG session during Sapphire including significant discussion about their use of IBM Power Systems.  I was particularly struck by how Joe Caruso, Director, ERP Technical Architecture at Pfizer described how Pfizer tested a large BW environment on both a single scale-up Power System with 50 cores and 5TB of memory and on a 6-node x86 scale-out cluster (tested on two different vendors, not mentioned in this session but probably not critical as their performance differences were negligible), 60-cores on each node with 1 master node and 4 worker nodes plus a not-standby.  After appropriate tuning, including utilizing table partitioning on all systems, including Power, the results were pretty astounding; both environments performed almost identically, executing Pfizer’s sample set, composed of 75+ queries, in 5.7 seconds, an impressive 6 to 1 performance advantage on a per core basis, not including the hot-standby node.  What makes this incredible is that the official BW-EML benchmark only shows an advantage of 1.8 to 1 vs. the best of breed x86 competitor and another set of BW-EML benchmark results published by another x86 competitor shows scale-out to be only 15% slower than scale-up.  For anyone that has studied the Power architecture, especially POWER8, you probably know that it has intrinsics that suggest it should handle mixed, complex and very large workloads far better than x86, but it takes a customer executing against their real data with their own queries to show what this platform can really do.  Consider benchmarks to be the rough equivalent of a NASCAR race car, with the best of engineering, mechanics, analytics, etc, vs. customer workloads which, in this analogy, involves transporting varied precious cargo in traffic, on the highway and on sub-par road conditions.  Pfizer decided that the performance demonstrated in this PoC was compelling enough to substantiate their decision to implement using IBM Power Systems with an expected go-live later this year.  Also, of interest, Pfizer evaluated the reliability characteristics of Power, based in part on their use of Power Systems for conventional database systems over the past few years, and decided that a hot-standby node for Power was unnecessary, further improving the overall TCO for their BW project.  I had not previously considered this option, but it makes sense considering the rarity of Power Systems to be unable to handle predictable, or even unpredictable faults, without interrupting running workloads.  Add to this, for many, the loss of analytical environments is unlikely to result in significant economic loss.

Also in a Sapphire session, Steve Parker, Director Application Development, Kennametal, shared a very interesting story about their journey to HANA on Power.  Though they encountered quite a few challenges along the way, not the least being that they started down the path to Suite on HANA and S/4HANA prior to it being officially supported by SAP, they found the Power platform to be highly stable and its flexibility was of critical importance to them.  Very impressively, they reduced response times compared to their old database, Oracle, by 60% and reduced the run-time of a critical daily report from 4.5 hours to just 45 minutes, an 83% improvement and month end batch now completes 33% faster than before.  Kennametal was kind enough to participate in a video, available on YouTube at: https://www.youtube.com/watch?v=8sHDBFTBhuk as well as a write up on their experience at: http://www-03.ibm.com/software/businesscasestudies/us/en/gicss67sap?synkey=W626308J29266Y50.

As I mentioned earlier, SAP snuck in a non-announcement about VMware and how a single production VM is now supported with VMware 6.0 in the week prior to Sapphire.  SAP note 2315348 – describes how a customer may support a single SAP HANA VM on VMware vSphere 6 in production.  One might reasonably question why anyone would want to do this.  I will withhold any observations on the mind set of such an individual and instead focus on what is, and is not, possible with this support.  What is not possible: the ability to run multiple production VMs on a system or to mix production and non-prod.  What is possible: the ability to utilize up to 128 virtual processors and 4TB of memory for a production VM, utilize vMotion and DRS for that VM and to deliver DRAMATICALLY worse performance than would be possible with a bare-metal 4TB system.  Why?  Because 128 vps with Hyperthreading enabled (which just about everyone does) utilizes 64 cores.  To support 6TB today, a bare-metal Haswell-EX system with 144 cores is required.  If we extrapolate that requirement to 4TB, 96 cores would be required.  Remember, SAP previously explained a minimum overhead of 12% was observed with a VM vs. bare-metal, i.e. those 64 cores under VMware 6.0 would operate, at best, like 56 cores on bare-metal or 42% less capacity than required for bare-metal.  Add to this the fact that you can’t recover any capacity left over on that system and you are left with a hobbled HANA VM and lots of leftover CPU resources.  So, vMotion is the only thing of real value to be gained?  Isn’t HANA System Replication and a controlled failover a much more viable way of moving from one system to another?  Even if vMotion might be preferred, does vMotion move memory pages from source to target system using the EXACT same layout as was implemented on the source system?  I suspect the answer is no as vMotion is designed to work even if other VMs are currently running on the target system, i.e. it will fill memory pages based on availability, not based on location.  As a result, this would mean that all of the wonderful CPU/memory affinity that HANA so carefully established on the source system would likely be lost with a potentially huge impact on performance.

So, to summarize, this new VMware 6.0 support promises bad performance, incredibly poor utilization in return for the potential to not use System Replication and suffer even more performance degradation upon movement of a VM from one system to another using vMotion.  Sounds awesome but now I understand why no one at the VMware booth at Sapphire was popping Champagne or in a celebratory mood.  (Ok, I just made that up as I did not exactly sit and stare at their booth.)

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May 26, 2016 - Posted by | Uncategorized | , , , , , , , ,

5 Comments »

  1. Another insightful post, many thanks Alfred. One thing, video is on the IBM site yet has vanished from youtube.

    Comment by Phil Morris | May 26, 2016 | Reply

    • Good catch Phil. Must have been a problem with the shortened link. I replaced it with the full link.

      Comment by Alfred Freudenberger | May 27, 2016 | Reply

      • Kennametal Youtube link still does not work.

        Comment by Bob Kuhn | July 4, 2016

      • Thanks Bob, updated the links … again.

        Comment by Alfred Freudenberger | July 8, 2016

  2. […] HANA      1      2      3      4   […]

    Pingback by Linux on POWER8 / OpenPOWER Resources – Power The Enterprise | August 31, 2016 | Reply


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