Challenging the Xeon

So what caused us to investigate the IBM POWER8 as a viable alternative to the mass market Xeon E5s and not simply the high-end quad (and higher) socket Xeon E7 parts? A lot. IBM sold its x86 server division to Lenovo. So there is only one true server processor left at IBM: the POWER family. But more importantly, the OpenPOWER fondation has a lot of momentum since its birth in 2013. IBM and the OpenPOWER Foundation Partners like Google, NVIDIA, and Mellanox are all committed to innovating around the POWER processor-based systems from the chip level up through the whole platform. The foundation has delivered some tangible results:

  • Open Firmware which includes both the firmware to boot the hardware (similar to the BIOS) ...
  • ... as OPAL (OpenPOWER Abstraction Layer) to boot and launch a hypervisor kernel.
  • OpenBMC
  • Cheaper and available to third parties (!) POWER8 chips
  • CAPI over PCIe, to make it easier to link the POWER8 to GPUs (and other PCIe cards)
  • And much more third party hardware support (Mellanox IB etc.)
  • A much large software ecosystem (see further)

The impact of opening up firmware under the Apache v2 license and BMC (IBM calls it "field processor") code should not be underestimated. The big hyperscale companies - Google, Amazon, Microsoft, Facebook, Rackspace - want as much control over their software stack as they can.

The resuls are that Google is supporting the efforts and Rackspace has even built their own OpenPOWER server called "Barreleye". While Google has been supportive and showing of proof of concepts, Rackspace is going all the way:

... and aim to put Barreleye in our datacenters for OpenStack services early next year.

The end result is that the complete POWER platform, once only available in expensive high end servers, can now be found inside affordable linux based servers, from IBM (S8xxL) and third parties like Tyan. The opinions of usual pundits range from "too little, too late" to "trouble for Intel". Should you check out a POWER8 based server before you order your next Xeon - Linux server? And why? We started with analyzing the available benchmarks carefully.

A Real Alternative? Reading the Benchmarks
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  • Kevin G - Saturday, November 7, 2015 - link

    If all you do is just mount the network volume to use the data, then likely nothing at all. While binaries do have to be modified, the file systems themselves are written to store data in a single consistent manner. If you're wondering more if there would be some overhead in translating from LE to BE to work in memory, conceptually the answer is yes but I'd predict it be rather small and dwarfed by the time to transfer data over a network. I'd be curious to see the results.

    Ultiamtely I'd be more concerned with kernel modules for various peripherals when switching between LE and BE versions. Considering that POWER has been BE for a few generations and you did your initial testing using LE, availability shouldn't be an issue. You've been using the version which should have had the most problems in this regard.
  • spikebike - Friday, November 6, 2015 - link

    So basically power is somewhat competitive with intel's WORST price/perf chips which also happen to have the worst memory bandwidth/CPU. Seems nowhere close for the more reasonable $400-$650 xeons like the D-1520/1540 or the E5-2620 and E5-2630. Sure IBM has better memory bandwidth than the worst intels, but if you want more memory bandwidth per $ or per core then get the E5-2620.
  • JohanAnandtech - Saturday, November 7, 2015 - link

    It is definitely not an alternative for applications where performance/watt is important. As you mentioned, Intel offers a much better range of SKUs . But for transactional databases and data mining (traditional or unstructured), I see the POWER8 as very potent challenger. When you are handling a few hundreds of gigabytes of data, you want your memory to be reliable. Intel will then steer you to the E7 range, and that is where the POWER8 can make a difference: filling the niche between E5 and E7.
  • nils_ - Wednesday, November 11, 2015 - link

    Especially if you're running software that doesn't easily scale out very well these are very competitive. And nowadays even MySQL will scale-up nicely to many, many cores.
  • Gigaplex - Friday, November 6, 2015 - link

    "Less important, but still significant is the fact that IBM uses SAS disks, which increase the cost of the storage system, especially if you want lots of them."

    The Dell servers I've used had SAS controllers, and every SAS controller I've dealt with supported using SATA drives. I'm pretty sure SATA compatibility is in the SAS specification. In fact, the Dell R730 quoted in this review supports SAS drives. There shouldn't be anything stopping you from using the same drives in both servers.
  • JohanAnandtech - Saturday, November 7, 2015 - link

    You are absolutely right about SATA drives being compatible with a SAS controller. However, afaik IBM gives you only the choice between their own rather expensive SAS drives and SSDs. And maybe I have looked over it, but in general DELL let you only chose between SATA and SSDs. And this has been the trend for a while: SATA if you want to keep costs low, SSDs for everything else.
  • TomWomack - Sunday, November 8, 2015 - link

    And mounting a storage server made out of commodity hardware over a couple of lanes of 10Gbit Ethernet if you don't want to pay the exotic-hardware-supplier's markup on disc.
  • Gunbuster - Friday, November 6, 2015 - link

    SAP and IBM AIX servers... I guess if you want to blow out your entire IT budget in once easy decision...
  • Jake Hamby - Friday, November 6, 2015 - link

    I forgot to mention: VMX is better known as AltiVec (it's also called "Velocity Engine" by Apple). It's a very nice SIMD extension that was supported by Apple's G4 (Motorola/Freescale 7400/7450) and G5 (IBM PPC 970) Macs, as well as the PPC game consoles.

    It would be interesting to compare the Linux VMX crypto acceleration to code written to use the newer native AES & other instructions. In x86 terms, it'd be like SSE-optimized AES vs. the AES-NI instructions.
  • Oxford Guy - Saturday, November 7, 2015 - link

    I had a dual 450 MHz G4 system and AltiVec was quite amazing in iTunes when doing encoding. Between the second processor and the AltiVec putting things into ALAC was very fast (in comparison with other machines at the time like the G3 and the AMD machines I had).

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