The IBM POWER8 Review: Challenging the Intel Xeon
by Johan De Gelas on November 6, 2015 8:00 AM EST- Posted in
- IT Computing
- CPUs
- Enterprise
- Enterprise CPUs
- IBM
- POWER
- POWER8
Taking a Closer Look At IBM's S822L
The S822L was mounted in the Xeon server dominated racks inside our experimental datacenter. The build quality of both the rails and server were apparent, a "locking mechanism" made sure the server was easy to mount without a screwdriver and was kept firmly at its place.
The system booted by using the Flexible Service Processor (FSP), which is comparable to the Baseboard Management Controllers as they are both components that allow you to manage and monitor your server thanks to the IPMI specification. The main difference with Xeon system is that the FSP and its related firmware and software is the only way you can control your system. There is no "BIOS" screen or BIOS configuration setup, everything has to be configured and booted via the FSP software. You could say that the "BIOS" and "BMC management software" are now integrated into one central firmware.
To power on the S822L, you have to access the FSP using the open-source IPMItool. Once the server is booted up, the "petitboot" bootloader of OPAL (the OpenPOWER Abstraction Layer firmware) takes over. It scans all bootable instances (disks, network, optical, etc.) for operating systems, and is similar to the GRUB bootloader. From there, you can install Linux like you would on an x86 system.
The cover was covered with a lot of interesting service information about the upgrading and replacing the hardware.
Once we removed the cover, lots of expansion slots became visible.
No less than nine hot plug (!) low profile PCIe Gen 3 slots are available. Four of them are x16, ready for some GPU action. Five are x8. Only one of the PCIe slots is used for the standard quad-gigabit Ethernet adapter. We also had one Emulex FC card installed.
Also installed were two PowerPC based SAS RAID controller(s), capable of RAID-6 and all common RAID levels, which connectto a dual backplane that offers 12 Small Factor Form (2.5 inch) drives. These drives can be SAS SSD or hard disks, which is a reliable but rather expensive storage choice. A DVD drive was also present, which allowed us to install Linux the old-fashioned way.
At the back we find two hot-swappable PSUs, four gigabit Ethernet interfaces, two USB 2.0 ports, an HMC dual-gigabit interface (an HMC is a hardware applicance that can manage several IBM servers) and one system port.
The server is powered by two redundant high quality Emerson 1400W PSUs.
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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).