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A Server for All Seasons
Author: Kris Neely


Unless you have been living in a cave for the past month or so, you have probably noticed one or more of the road shows, Webcasts, or articles on the new iSeries i5. What do the i5 announcements mean to those of us who dwell on the server consolidation, networking, and general infrastructure side? (As opposed to those folks who would rather write RPG than eat.) It means a lot.

The Big Picture

The i5 announcement is huge, particularly from infrastructure and server consolidation standpoints. Think about this fact alone: with the i5, you now have access to a server that can simultaneously run every operating system IBM offers, except Z-OS. (Remember when all an AS/400 did was run OS/400?)

Today's iSeries can handle these workload producers: OS/400, POWER SUSE Linux, POWER Red Hat Linux, PC-based Linux (on the IXS), AIX (later this year), Domino, A Java Virtual Machine (JVM), Tivoli, and "closely coupled" Windows OS (which I'll explain in a moment). IBM has also increased the number of possible virtual Ethernet connections to over 4,000. That's more than most iSeries shops will ever need. Add in Logical Partitioning (LPAR) capabilities and what have you got? A server for all seasons, in my humble opinion.













           Model 520




Model 570 Although it is not an official IBM term, I use a description called closely coupled Windows. When you use an Integrated xSeries Server (IXS) or an Integrated xSeries Adapter (IXA) to run the Windows OS, you're leveraging iSeries DASD in place of Intel-based storage (among other things). You're also using IBM-certified xSeries Intel-based hardware to work with your iSeries. That fact is important because without such certification and assurances, you and your IT staff will be doing the "does-this-device-driver-work" dance in no time. With the set of xSeries hardware that works with the IXAs, for example, you avoid device-driver problems. (You avoid this issue by default with the IXS, which is an iSeries internal card, and therefore it has no one-to-one comparison in the "real" world.)

And speaking of the IXS, how close does a physical device have to be to be considered "closely coupled"? I'd say a device that fits inside another one qualifies as close.

Yet even the IXA (an external adapter) in a rack-mounted i5 configuration works this way: rack-mounted iSeries/HSL cable/rack-mounted xSeries server. Tidy. One rack-mounted server sitting right on top of another, with one cable connecting the two. Again – how much more closely coupled would you want?

Add in virtual Ethernet (not to mention virtual I/O) and you have a stack that couples just about as closely as you could get. Sure, Windows running native on the iSeries would be (arguably) closer, but we're dealing in today's reality. And today's iSeries reality has a lot of infrastructure-related options.

Options, Options
Now that you have an idea of the workload environments the iSeries can support, let's look at some of the architectural/infrastructure options those environments present. For example, with the i5, you now will be able to decide which version of Linux you'd like to run: POWER-based Linux on the i5 (or POWER 4-based) iSeries, or PC Linux on the IXS. All things considered, the difference is not huge from a technical perspective. But from an available applications perspective, the difference is gigantic, since far more applications are available for PC Linux than for POWER Linux.

The applications go far beyond the simple infrastructure applications many iSeries shops seem to equate with Linux. From CRM applications to MRP applications and beyond, PC Linux offers a host of new applications that can help make an iSeries-based organization more competitive, efficient, and cost effective. If your organization decides it likes a given PC Linux application, you never know, maybe IBM will be interested in convincing the vendor to port the application over to POWER Linux.

Leveraging Linux on POWER or PC gives iSeries management whole new levels of infrastructure and architectural dexterity (especially with sub-CPU Linux LPARs on iSeries). Perhaps your firm has been using Apache on PC Linux. Now you can migrate Apache to the iSeries and let the iSeries manage storage for Apache. Then you can leverage virtual Ethernet to connect Apache to OS/400. Now you have a secure, scaleable Apache environment with a one-button backup to tape. You have the same Linux and Intel elements, but now you have an environment that is more scalable, more secure, and simpler. You also no longer have to write checks to switch or router vendors.

Speaking of Linux, remember to step back and think about the placement of that operating system from a perspective other than that of mere capability. Think about it from the perspective of scalability.

Earlier, I mentioned sub-CPU Linux LPARs, which are an often-overlooked iSeries advantage from an architecture perspective. IT professionals are programmed (pun intended) to think of servers and applications in terms of full CPU allocations. For example, they forget than many Linux applications simply don't need 100% of a POWER 5 processor. The ability to allocate, say, one-half of a processor to a Linux task, and then dynamically add additional percentages of the processor as needed is a huge advantage. Keep that in mind as you explore the options for Linux in an i5 environment.

Think about the server consolidation and related infrastructure possibilities associated with AIX on i5. For example, imagine this scenario. With the i5, you can move your AIX-based servers into the i5 and consolidate storage onto the i5. You eliminate the need for network hardware (virtual Ethernet again) to connect the AIX and OS/400 environments, and you can do it at an attractive price. Moreover, porting other UNIX-based applications to AIX is possible, and can sometimes be fairly straightforward. (To be fair, some UNIX applications simply cannot be ported to AIX for technical or cost reasons.) With the i5, you have a server and network environment you can simplify, consolidate, and manage efficiently.

It's a Wrap
As you have seen, the i5 announcement adds to the architectural capabilities of the iSeries, making it arguably the most flexible server platform ever. The i5 is capable of running multiple operating systems, and in some cases, even running multiple instances and competing versions of operating systems. In the end, today's i5 platform is truly a server for all seasons.

Now you need to take time to consider how best to deploy just two of the operating environments of the i5. Get together with your iSeries teammates and take time to review the i5 announcement in more detail. The AS/400 has come a long way since 1988, and so have you. Today's iSeries managers and programmers have to master some of the most technically complex commercial hardware and software ever created. Getting together to discuss how to use all the pieces and parts of those technologies is a task best left to groups because, as you've seen, there are options on top of options.

In the next article, I will continue discussing the new i5 announcement and how it affects the architectural, network, server consolidation, and IT optimization options available to iSeries and AS/400 installations.

Stay tuned!
Kris Neely is IBM America's iSeries Sales Manager for Windows Integration and Server Consolidation. He is also an IBM Certified Senior Consulting IT Architect and is OS/400 Certified. The author of several books, instructional videos, and hundreds of articles on iSeries and information technology in general, Kris has over 25 years of practical, hands-on experience in information systems at every level from computer operator to CIO. An award-winning speaker and former member of the Board of Directors of COMMON, Kris is also a member of the IEEE, the ASPIC, the Northern California Association of Science Writers, and the National Association of Science Writers. He can be contacted at: