The Case for Linux on Power

People occasionally ask me why they should run Linux on Power hardware. Their first inclination is typically to deploy Linux on some inexpensive commodity x86 hardware. They don't even think about the benefits of running Linux on Power. They believe they'll need to recompile their binaries to even get them to run. They assume the extra effort will outweigh the benefits.

As I've noted in "Lx86 Works as Advertised," you can run unmodified x86 binaries on top of Linux on Power by using Lx86. From IBM's PowerVM Lx86 for x86 Linux applications Web site:

"PowerVM Lx86 supports the installation and running of most 32-bit x86 Linux applications on any System p or BladeCenter model with POWER6, POWER5+ or POWER5 processors, or IBM Power Architecture technology-based IBM BladeCenter blade servers. It creates an x86 Linux application environment running on POWER processor-based systems by dynamically translating x86 instructions to Power Architecture instructions and caching them to enhance performance, as well as mapping x86 Linux system calls to Linux on POWER system calls. Best of all, no native porting or application upgrade is required for running most x86 Linux applications."

Recently I was at a session where Linux on Power was discussed. And a few benefits of running Linux on Power were raised that I think are worth noting.

1. IBM PowerVM virtualization technology provides the option of dynamically optimizing the mix of processor, memory, disk and network resources. This means that I can add just another LPAR to my frame to handle that Linux workload. Instead of going out and buying and managing another server, I just give it the necessary LUNs, shared Ethernet, memory and CPU allocation, and away I go.
2. Reliability matters. The IBM whitepaper "IBM Power Platform Reliability, Availability and Serviceability," is well worth reading. I'll highlight this point: "The base reliability of a computing system is, at its most fundamental level, dependent upon the intrinsic failure rates of the components that comprise it. Very simply, highly reliable servers are built with highly reliable components." Do you want your Linux machines running on commodity hardware, or do you want them running on reliable hardware?
3. Device drivers don't matter so much. Often you may find that there are no drivers for your hardware. However, this is less of an issue with Linux on Power, especially in a virtualized environment. Using a VIO server, how you get to the storage or the network isn't a concern; your VIO server handles that. You're just using a virtual adapter in your client LPAR. This allows you to use enterprise hardware without waiting for a device driver.
4. Power is less expensive overall. This is highlighted in an article on supercomputingonline.com titled, "IBM Power Systems Again Trump Latest Intel Offering, Highlights Total Systems Value." From the article: "According to an International Technology Group (ITG) report, three-year costs for use of Power servers ranged from 25-33 percent less than those built around commodity x86 servers in an SAP solution-based environment. Conversely, the three-year cost for the use of x86 servers was 48 percent higher than for Power servers in the retail industry, 49 percent higher in manufacturing, and 33 percent higher in energy. Costs outlined in the report include hardware acquisition and maintenance, systems software licenses and support, including operating systems and virtualization tools, personnel and facilities."

Obviously in some cases, running Linux natively on x86 hardware is the best choice. However, instead of dismissing the idea out of hand, take the time to research whether it might make sense to add a few LPARs to an existing enterprise frame.

On an unrelated note, check out this recent IBM statement of direction:

"IBM plans to provide an upgrade path from the current IBM Power 595 server with 12X I/O to IBM's next-generation POWER7 processor-based high-end server. The upgrade is planned as a simple replacement of the processor books and two system controllers with new POWER7 components, within the existing system frame. IBM also plans to provide an upgrade path from the current IBM Power 570 server with 12X I/O to IBM's next generation POWER7 processor-based modular enterprise server."

This is good news if you've been debating whether to order a POWER6 server now or wait until POWER7 comes out. Now you can have the best of both--POWER6 performance now, and POWER7 when it ships.

Comments

[Andi V.]

You are right, from the technical pov Linux is NOT a problem on IBM platforms, especially since IBM has been supporting it generously for years. Coming from x86/SPARC world I was amazed how beautifully AIX integrates RPM, etc. Still, when SPEC2006 lists a benchmark for an HP DL380 G5 ($7,000 machine) of 61, and for a POWER6 8203-E4A (a machine of $27,000) lists 101 (CINT 2006 Rates), it is difficult to make a case for Power platform. And I don't even mention that I don't have to deal with HMC and throwing the pizza-box that supports it with every new AIX release (had to do it), I don't have to exactly match the firmware or else the OS crashes and so on...