Which Way the Wind Blows for i5-Windows Integration

The use of Windows-based applications and databases in iSeries shops and their integration with the OS/400 platform will probably be one of the most wrestled with tasks companies deal with in the foreseeable future. By most estimates, nine out of ten iSeries shops have Windows servers for application or infrastructure purposes, beginning with file serving, and including such things as e-mail, SQL databases, Web serving, distribution of desktop tools such as Word and Excel, and, yes, even line of business applications. iSeries shops are deploying Windows apps and there is a need to lash them to the iSeries so they can get data and interface with RPG and COBOL applications.

That’s easy to say, but hard to do. And the right way to integrate these platforms has less to do with whether you are an IBM fundamentalist or Microsoft zealot than it does with the hand you are dealt by circumstances at your own company. Companies have people, processes, and business rules in place, and they have a history with various platforms and budgets and investments for them to boot. Then there is the Linux factor. Although this is by and large a Windows integration issue today at most OS/400 shops, it is more precisely an integration issue involving X86 and X64 servers, which increasingly run the Linux operating system.

The Windows integration effort goes back to the mid-1990s, the heyday of the AS/400. Windows integration has gone through multiple generations of technology that correspond with Windows’ evolution from entry-level enterprise player–think of Windows NT back in 1994–to something that is part and parcel of the computing landscape. Because Windows integration on the OS/400 platform tends to be a consideration during upgrade cycles, the advances in Windows integration methods tend to be tied to AS/400 and iSeries upgrade cycles as much as Microsoft’s Windows upgrade cycles. Not that everyone upgrades in unison, but when end-of-support announcements are made, it does have the effect of lighting a fire under companies that normally would not plan ahead.

So when you look at events such as the shift from NT to Windows Server 2000 and from Windows Server 2000 to Windows Server 2003, there is a noticeable corresponding impact on buying new servers, new databases, and new storage. You can also view ongoing factors such as the business implications of the Internet and the increasing presence of Microsoft’s SQL Server database management system in iSeries shops–particularly for business intelligence workloads, since the SQL Server online analytical processing database that debuted with SQL Server 2000 was cheap and easy to use–as also adding momentum to Windows installations at OS/400 shops. Windows is also a popular platform for new workloads, such as customer relationship management, and, of course, server implementations of office automation programs.

Ironically, there is not a strong track record of xSeries consolidations on the iSeries. “Most of the customers we see at conferences seem to have older systems and no intention of upgrading to the hardware requirements they would need to do that,” says David Bishop, a director of Microsoft’s global ISV architect team. “They tend to build outward with their own Windows boxes.” In terms of server consolidation projects, Bishop and people within the iSeries ISV community are much more familiar with consolidation of iSeries and AS/400s onto newer and more powerful i5 boxes.

Windows integration on the iSeries is currently accomplished with either the Integrated xSeries Server (IxS) or the Integrated xSeries Adapter (IxA). The IxS is a card that plugs into the iSeries system or its I/O towers. The number of IxS cards that can be put into an AS/400, iSeries, or i5 machine varies depending on the iSeries model. For instance, on the new System i5 machines, it ranges from 18 IxS cards on the i5 520 to 60 IxS cards on the i5 595. The current IxS is limited to a 2.0 GHz Pentium M processor, which is no speed demon but nonetheless satisfactory for most Windows servers that are running modest infrastructure workloads. The IxA, on he other hand, uses the High Speed Link I/O connections of the iSeries to link external xSeries servers equipped with special cards to the iSeries. The current System i5 line can have from 8 to 57 IxA cards, depending again on the model. The IxA links to xSeries machines with one, two, four, or eight processor sockets in an SMP setup; some of these machines can now be equipped with “Paxville” dual-core Xeon DP or MP processors, which makes them very powerful in terms of raw performance. Servers that need a lot of processing power–particularly application and database servers–really require the IxA.

IBM has put out a statement of direction that it will be selling the IxS for many years to come, but will be replacing the IxA card with an Internet SCSI (iSCSI) adapter that can link into any xSeries server–and probably into any X86 or X64 server that is equipped with the right devices. The iSCSI link does what the name suggests–it provides a SCSI peripheral link using an Ethernet-based IP connection as the transport medium for the data. With the IxA approach, IBM was only able to put the X86-side of the IxA link into machines that had room for the extra electronics. By moving to an iSCSI link, Ethernet becomes the transport, and the Gigabit Ethernet ports in the System i5 and most X64 servers today are fast enough to integrate Windows servers and i5 storage and databases. If you need added bandwidth, you add more iSCSI links between the two machines.

Real World Use

IBM estimates that, over the years, iSeries shops have acquired tens of thousands of the IxS servers running Windows or IxA cards linking to Windows servers. That estimate comes from George Gaylord, the product marketing manager for integrated xSeries on the iSeries. When pressed to be more precise, Gaylord said the number is probably fewer than 50,000 and likely something close to 30,000. In any case, the number of IxS and IxA devices dwarfs the number of AIX and Linux partitions that are in use today, which stands to reason since running AIX and Linux on the iSeries is a relatively new option. Having said that, the number of Windows boxes that are not directly linked to the iSeries (but probably loosely linked through normal Ethernet networks) is, based on our estimates, on the order of a million machines. (Think of it: There are well over 200,000 OS/400 shops, and many of them have multiple Windows servers.)

If there is such a thing as the typical integrated Windows implementation (meaning using the IxS or IxA), Gaylord would describe it as an iSeries shop with an IxS for Active Directory and some file serving, and a Citrix Systems Presentation Server running other Microsoft applications to 50 or 100 iSeries users. Primarily these are small to midsize companies that have maybe one Windows administrator in the IT department and he is managing a handful of servers and doing routine maintenance.

“I see Windows integration happening as smaller projects.” Gaylord says. “Not projects involving hundreds of servers. I see 5, 10, or 15 older Windows servers being consolidated in shops that are trying to go from Windows NT to Windows 2000.” Presumably, there are shops trying to move to Windows Server 2003, too, since Windows 2000 is getting a little long in the tooth.

“We see a lot of file serving, a lot of Active Directory, and other small applications,” Gaylord says. “But in recent years, the tendency is to go toward IxA. Where there was once stability concerns when doing hard-core line of business stuff with Windows NT, that has improved with Windows 2000 Server and again with Windows Server 2003. Customers are more confident. Personally, I would not put Windows reliability in the realm of i5/OS, but some apps are not available for i5/OS, so they are put in a Windows server environment. For example, Citrix is an app that has been around for a while and it does not run on i5/OS. Citrix delivers Windows applications to various clients, including a browser. Companies can put it on a two-way xSeries for every 30 to 50 users. Meanwhile, all the data for all those desktops is stored on the iSeries system.”

Gaylord sees iSeries shops buying bigger Windows servers–two-ways, in particular–that are used for line of business applications in addition to those running on the iSeries.

“One of the reasons we started with the IxA was to do two-way and four-way processing,” he explains. “We see customers running things like SQL Server databases that need this. A lot of customers are buying two-ways as a standard these days.”

As processing power increased, changes needed to be made in order to accommodate the integration. When the xSeries introduced the 3.6 GHz and later the 3.8 GHz servers, the IxA kept pace with the xSeries 346 and xSeries 366 in order to deliver more processing power. The IxS had hit the ceiling with 2 GHz due to the amount of heat the higher performance chips produced. It remained viable because enough companies didn’t require higher performance for a great many Windows applications.

Consolidate on the iSeries or the xSeries?

As the xSeries servers continued to grow in order to accommodate more complex applications and heavier database loads, and since the introduction of the BladeCenter blade server over three years ago, the question of why not consolidate Windows servers on larger Windows servers becomes relevant. The compactness and simplicity of blades and the price/performance of bigger rack-mounted X64 boxes has certainly proved to be compelling.

Gaylord says the key to that option is determining what to do about storage. “It can make sense in some situations to consolidate to BladeCenter, but centralized storage choices are usually a storage area network or network attached storage.”

Managing storage on the X64 side requires the acquisition of additional servers and software, plus the time it takes someone to maintain the system. An alternative in many cases, Gaylord says, is to carve additional storage from the iSeries where centralized storage and backup becomes an important benefit. In heterogeneous server circumstances, where virtual storage becomes part of the equation, the attached xSeries boxes can also tap into the same Virtual Ethernet that i5/OS, AIX, and Linux partitions are using.

Before coming to a conclusion regarding a centralized storage plan, one major obstacle has to be overcome. The iSeries administrator and the Windows administrator need to sit down and figure out how to optimize the setup for their environment. It seems simple, but it’s not because these people tend to only see things from their own platform perspectives. The overall good of the company is sometimes lost in the bickering.

In small to midsize shops where the iSeries is clearly the dominant architecture, such a plan has a good chance of taking hold. And this is exactly where Gaylord claims the greatest successes have been realized.

However, in working this segment of the iSeries market, the success of xSeries BladeCenter server consolidation has put a crimp in the iSeries server consolidation plan. BladeCenter cannot be connected to the i5 platform because it does not use the same communication protocol as the IxA. The BladeCenter supports Fibre Channel connections for storage, which has much higher performance option compared to the IxA High Speed Link, which itself has more bandwidth than the IxS. While Fibre Channel is nice, iSCSI is simpler and cheaper.

Eventually iSCSI will replace the IxS and the IxA, but Gaylord says any discussion of timetables for the sunsetting of the IxS and IxA technologies is premature. “As iSCSI rolls out and matures, its advantages will bring customers,” Gaylord says. “However, the iSCSI link will not force IxS and IxA customers to abandon their investment and move to iSCSI. These approaches will co-exist. We plan to continue to support those customers.”

It seems highly likely that BladeCenters will gain the lion’s share xSeries consolidations in the future–provided customers need all that processing power–and if those BladeCenters are going to be managed on the iSeries and storage is going to be consolidated there, it is clear that the iSCSI connection will become dominant. It is equally clear that the day of the 2 GHz IxS server is numbered. In an interview with IT Jungle during the Fall 2006 COMMON Conference, Jim Herring, director of iSeries product management and business operations, commented on iSCSI and the migration from IxS and IxA, which he thought would take place after approximately one year.

Gaylord did not feel comfortable talking about that schedule. He provided this example to support his belief that IxS and IxA will be around longer than one year. “Let’s say a customer on an i5 520 buys an IxS for the system unit. The customer later buys a handful of xSeries servers and then attaches them with the IxA. You can only put eight of those on a 520. That’s more than enough for many customers. But there are customers who want more than eight on a 520. In order to get more, they would have to go to a 550. Maybe they don’t need that extra processing power for other applications. With iSCSI, they could add servers, keep what they have invested in the IxA, and they can grow. Two years from now they may cycle the IxA out and replace it with an iSCSI environment. We see that as a natural progression.”

“Because IBM’s xSeries is such a great Windows box and IBM has brought out tools like Tivoli, there is not a good value to do Windows consolidation on iSeries when customers can use an IBM blade server and IBM software,” says David Delisi, senior program manager for developer and platform evangelism at Microsoft. “Even if the IBM IxS option that allows Windows applications to run on the iSeries was made less complicated and with better performance, most companies are not going to consolidate Windows servers on iSeries boxes. And, running Windows natively on iSeries (in a partition like AIX and Linux) faces large technical hurdles and is not likely to happen any time soon. It is not in the pipeline.”

As part of this series of articles, we have published articles reviewing the integration of AIX on the iSeries and Linux on the iSeries. Those efforts are relatively new and momentum has yet to really build. The integration of X86 and now X64 servers with the AS/400, iSeries, and now System i5 is clearly farther down the road than AIX and Linux logical partitions, but then again, IBM has been offering inboard Windows servers for more than a decade.

It could be that the small server consolidation projects are not the glamorous things that get a lot of airplay in the marketplace, but that seems to brush aside the fact that the iSeries customer base is very ho-hum about the benefits of tightly integrated Windows servers–30,000 tightly linked machines versus about 1 million or more overall Windows boxes in the OS/400 ecosystem. That’s a 3 percent market penetration. With Microsoft nearing the release date of its Windows Vista Server, it will be soon be sunsetting support for Windows 2000 and there should be a rise in activity for X64 integration. On the iSeries side, new i5 hardware and a new operating system will help companies focus on integration issues as well. Add the iSCSI release and the timing is right for making some advances.

When companies are using an X64 email server for order confirmation, another X64 as a Web server that might be front-ending orders for an ERP environment, a third X64 as a WebSphere server doing front end work for an ERP suite, and a fourth as an Active Directory server that is critical because clients are using it to get to the iSeries, the need for iSeries integration is established. How well X64 integration on the iSeries goes during the next two years will say a lot about how well the iSeries is destined to due overall.

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