IBM’s sturdy iSeries 825 is built like a battleship and priced to match

Two short phrases describe IBM’s eServer iSeries 825 server: You’ll pay through the nose, but you’ll get what you pay for. This hardware/software combo starts at $160,000 for the base system, four to six times what you’d pay for a similar-appearing multiprocessor Xeon box. But the i825 is so robust that the only way to kill it would be to either yank out its dual 208-volt power cords or hit it with a truck. And I don’t mean a wimpy little SUV either. This is the type of server that a medium- or large-size company can use to install those true mission-critical applications, such as accounting, e-mail, or an e-commerce Web farm, and not have to worry that it will crash.

So, what is an iSeries server? It’s a proprietary 64-bit minicomputer, formerly called the AS/400, based on IBM’s Power4 processor. It runs the proprietary OS/400 operating system, currently at version 5, release 2, as well as Linux; plus it runs Windows on dedicated processor cards.

The i825 system I tested contained six 1.1GHz processors and 8GB of RAM. This model can also be purchased with only three processors and expanded to 48GB of RAM.

The iSeries delivers an incredible amount of expandability. The system I tested had 10 36GB hard drives and 10 PCI-X slots. Using expansion chassis, you can extend each server up to 58TB of disk space and add dozens of additional silos. The server also contains hot-swap power supplies, a DVD-ROM drive, and an Ultrium tape backup. Nearly everything on the iSeries is hot-swappable, including processor cards, PCI cards, and disks, which I enjoyed testing.

For all its power, the i825 I tested is a midlevel, midrange machine. IBM sells baby models that have only one or two processors — suitable for developers or field offices — as well as monsters with 32 1.3GHz processors and room for 256GB of RAM and 144TB of disk space. The company also offers upgrades to convert an older iSeries box to an i825.

On the iSeries, you can now run as many as 31 separate instances of Linux concurrently with OS/400, each with its own set of applications, and dedicated disk and network resources. If one instance of Linux crashes, it won’t affect the rest of the system at all. The trade-off is that if many instances of Linux are running and they’re heavily laden, the system’s overall performance degrades. (Solution: Add more memory.)

The server can also run Java applications natively on OS/400 or the WebSphere app server. In mid-July IBM released a special version of WebSphere for Linux running on the iSeries box. Why would you want that? It simplifies the process of migrating applications running on a standard Linux server to the i825 or allows a hosting company or datacenter to present the appearance of a pure Linux solution to its customers.

IBM also offers x86-based Windows servers cards that can be inserted into the i825’s PCI slots. Each card includes its own Pentium processor and memory but shares the iSeries’ disks and network cards. IBM says that as many as 60 of these cards can be inserted into a single server.

But that doesn’t mean that those apps will run faster on the i825 than on commodity x86 servers because they don’t — each app’s speed is a function of clock speed. The iSeries server is like a Mack truck, not a Maserati. It’s designed for robustness and for handling nonstop transactions in parallel, not for sheer speed while executing individual applications.

The 64-bit iSeries architecture provides wide I/O channels, plenty of storage, and a huge flat-address space that makes it ideal for databases. But the clock speed is relatively slow, and there are only six processors. If you have applications that need to do a lot of number crunching, you’d be better off with a four-way, 3GHz Xeon-based system running Unix, Linux, or Windows. To put that in practical terms, put the database and data warehouse on the i825, and perform the BI analysis on a faster PC server.

In short, an iSeries migration is expensive, but in a large server farm, the system would ultimately reduce hardware costs, improve use of storage assets, and simplify management. And you’d have to hit the server with a truck to crash it.