Tuesday, December 16, 2014

If you can't do it with Power, you can do it with MORE Power

IBM has released their Power8 CPU and with that a bunch of servers and also some other news around this, like the OpenPower consortium that has been around for a year or so now. Besides IBM, Tyan and Google have announced that they are building systems around the Power8 CPU, with the a Tyan server being on sale for some $2800, but this is not a server with a high-end configuration, but it is in a 2U rack mount case and is extensible with more disks and RAM.

There is one thing with the Power8 CPU that sets it apart from the previous Power CPUs that is worth mentioning, which is the byte ordering or endianess of the CPU. The order of the bytes in value in a computer comes in two main flavours, the "Motorola style" AKA "big endian" which is how we write numbers in general, with the most significant digit (or byte in the case of computers) first, and then we have the "Intel style" or "Little endian" where the most significant byte comes last. All of this has little meaning to most of you so far. Thar Big endian is old school mainframe style, but is also used by many RISC CPUs. For those of you with a flair for weird facts one oddball of endianess was PDP-11, where each byte in a 16-bit part in a 32-bit word was swapped (this is called PDP-endian). And by the way, Oddball of Endianess would be a great name for a Country-Rock band (having at least 3 Telecaster equipped guitarists on stage).

What makes Power8 a bit different is that it supports operating systems using either big endian or little endian. Big endian is used by AIX and some Linuxes, but IBM is trying to get more Linuxes onto the little endian train. Among the Big endian Linuxes on Power8 are Red Hat and derivatives, like Fedora (note that CentOS isn't one of them, so far, as Centos 7 doesn't yet support Power at all, nor is 32-bit Intel supported anymore) as well as Debian and SUSE 11 (which will continue to be supported). The little endian Linuxes on Power8 so far includes SUSE 12 and Ubuntu 14.04.  But IBM really wants Linux on Power to run Little endian, so it seems that Debian is on it's way there and Red Hat 7.1 will also support Little endian. But to be honest, we don't have the full story yet.

There are some really good things with the Power8 architecture, like really good performance (see this one for example by MariaDB and IBM) and also it is a great platform for Virtualization / Cloud infrastructure. And all that fuzz with endianess will hopefully be history soon when we have all Linuxes on Power8, as well as x86_64 of course, running Little endian (thank you). And the Country-Rock band mentioned above could call their first record "Fuzz with Endianess".

So, I have convinced you? If so, I guess you want to know what it costs. Well, Power8 machines from  IBM starts at around $10.000, which is a lot it seems, but then you have to remember that used the way this type of system is probably mostly used, as a host for numerous virtual machines, then it is actually pretty reasonable. If you really want a less expensive machine, Tyan has one available which should sell for some $3.000 which is looking more reasonable. Eventually I guess Tyan will sell their motherboards, and the components in this, beside the CPU, is pretty standard stuff (DDR RAM, PCI buses, SATA disks etc). But the CPU is pretty expensive. Anyway, there is a way around all this, if you really want to try running Power8, and that is to use emulation, and once you get the hang of it, this works well, although slowly, but no so slow that you cannot test things on it (but too slow for production use I guess).

I'll show you how to set up an emulated Power8 system in a later blog post, so stay tuned and Don't touch that dial!


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