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Installing and running Linux on IBM p5 systems

Mixing Linux with p5 architecture can help your IT shop reap rewards in support, gain the capacity to run on a 32-way system and more.

A p5 system is one that runs on IBM Power architecture with the new Power5 chip. The Power5 chip, released in 2005, is the fifth generation of IBM's line of POWER processors. Power5 brings simultaneous multithreading capabilities through the new architectural design of its core.

But how does Linux play into p5 architecture? Well, you might want to install Linux on a pSeries server for any of the following three reasons:

  • You have existing IBM Unix hardware. PSeries servers let you create Unix, Linux or even AS/400 logical partitions (LPARs), and IBM offers considerable Linux support options that may benefit large IBM shops.
  • You need massive horsepower. With the 2.6 kernel, Linux can run on a 32-way system.
  • You want to run Linux with minimal resources and do not wish to purchase hardware that will rarely be utilized. With the micro-partitioning abilities of Advanced Power Virtualization (APV), you can assign as little as a tenth of a CPU to an LPAR.

Actually, APV offers some powerful features for reducing the need for extraneous hardware. Because each LPAR is a subset of physical and logical resources, you can treat an LPAR as a separate server and install a separate operating system on it, such as Linux. In fact, you can run multiple Linux installations simultaneously on a single eServer p5 server's LPARs. You can even share Linux and Unix partitions on the same CPU with APV's micro-partitioning features. Shared Ethernet, an APV feature that lets you use virtual adapters on your partitions using VIO servers, further lowers total cost of ownership (TCO) by removing the need for dedicated adapters in environments that may not need a lot of network bandwidth.

You can install Linux on an IBM pSeries server by way of either a CD-ROM or a network installation. This article will focus only on the CD-ROM method.

By setting up a boot server and an installation server, you can boot your eServer p5 server from the network and install Enterprise Linux on it. The boot server provides the required boot image and the installation server supplies the required installation media.

Red Hat, SuSE and TurboLinux all support Linux on the pSeries. Most users install either SuSE Linux Enterprise Server 9 (SLES9) or Red Hat Enterprise Linux 4 (RHEL4) because they run on the 2.6 kernel. Prior distributions running on earlier kernel releases will lack the full range of capabilities because the 2.6 kernel was optimized for the pSeries by IBM.

When you install Linux, you must use a Hardware Management Console (HMC), which is a management workstation that is used to create either Unix, Linux or AS400 LPARs. Interestingly enough, the management station runs on a PC with a stripped-down version of SuSE Linux. The older Regatta (p4) HMCs used Red Hat, but IBM changed its strategic direction with the Power5. IBM prohibits the use of these workstations for any purpose other than to manage your frames; IBM had a problem with users DVD movies on the HMCs, so the company slapped on more controls.

The IBM systems capable of running Linux on POWER are:

  • iSeries
  • pSeries
  • JS20 Blade Center
  • eServer p5
  • OpenPower

Read on for a walkthrough of the Installation using SLES9.

Start by activating your SLES9 partition. After you choose your managed system, choose Activate. This will take you to the activation screen, where you will set your boot-time options.

One available option when activating a partition is to open a Virtual Terminal Session. If you did not specify the diagnostics boot when you activated the partition, press 5 when you see the device checks on the bottom of the screen. This will force the system to boot in diagnostics mode, which will boot from the CD-ROM.

Please remember that if you're offsite you will have to use some kind of tool like VNC to connect to the Web browser on the HMC. For our purposes, let's assume that you are onsite and connected to your HMC.

At this point, you will see YaST as pictured below. The system will reboot after the first phase of the installation. After the reboot, it will prompt you to change the root password.

At that time, you will be prompted to configure your network and/or proxy settings. You can also choose whether to use VMC for remote administration of systems.

After you specify the additional users to create, the authentication type, and some additional options, YaST will write out the configuration and restart your services.

That's it. You'll get a screen saying the installation is finished. After you reboot your box, you'll get the login prompt. At this time the system can test your Internet connection, download release notes and look for updates.

Linux on the POWER can be an important part of your enterprise-wide architectural strategy, particularly if you are already working in an IBM shop or if your applications need the horsepower that the POWER can provide. The Advanced Power Virtualization capabilities of the p5 can bring tremendous flexibility to your environment and allow you to take full advantage of all your CPU resources. More than anything, Linux on the POWER truly demonstrates how Linux is ready for even the most demanding of infrastructure and application environments in your enterprise.

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