The eServer i5 Versus Windows Servers

Making a comparison between AS/400 and iSeries servers and Windows platforms has never been easy, and it has not gotten easier with the advent of the eServer i5 machines. It hasn’t gotten any more difficult, either, which is why I am happy to walk you through my price/performance analysis comparing the i5 Model 520 and 570 servers to 32-bit X86 machines running Windows Server 2003 and SQL Server 2000. Next week, I will do Linux servers.

Windows is the platform to beat in the midrange. Windows is now the volume leader for all server platforms (just inching past Unix for the first time, in the first quarter, in terms of revenue share), and it is one of two growing operating system platforms (the other being Linux, of course). IBM has to beat Windows on its own turf if it wants to start shipping larger numbers of machines and to protect its iSeries installed base against the pull of Windows.

As I have explained in past issues of this newsletter, there are a few general rules of thumb that you can use to talk about bang for the buck in the server market, and the eServer i5 has not changed these rules very much, in a general sense. (But in some specific ways, it has.) Generally speaking, a unit of processing capacity on an entry OS/400 server for applications that do not access the 5250 green-screen protocol is roughly twice as expensive as capacity on an entry X86 box; capacity on a midrange OS/400 or Unix box costs about twice as much as that on a midrange X86 box; capacity on a high-end OS/400 or Unix box costs twice as much as the midrange X86 machine; and mainframes cost about twice as much as big OS/400 or Unix boxes. The other rule is that a 64-bit IBM Power processor can do twice the work as a 32-bit Intel processor, at half the clock speed.

As my performance and price/performance comparison table indicates, the second rule still holds true. The problem with such simplistic rules as the first one I set out is that the boundaries between entry, midrange, and enterprise servers are shifting. Is a two-way Power5 server an entry box or a midrange box? It looks like an entry server but performs like a midrange machine. The distinctiveness of the word “midrange” is vanishing, as entry machines like the i5 Model 520 get all of the same features and benefits of the bigger boxes of years gone by, along with all the new goodies like logical partitioning and big cache memories.

Comparisons between the hardware embodied in i5 servers and Windows boxes are easy enough: you grab a rack chassis; throw in some processors, main memory, base disks, power supplies, and a tape drive; and there you have it. Technically speaking, the i5 server has a list price of zero–all of the revenue comes from the OS/400 Standard or Enterprise Edition. So, in theory, the base i5 hardware (chassis and processor) has infinite price/performance. (Yes, that was silly.) The point is, server hardware is fairly inexpensive these days, to the point that you could buy a lot of computing power for what you pay to acquire a car or a truck. This is a new phenomenon.

What has not become less expensive and less complicated is the software that actually makes these machines useful. And IBM’s packaging for the i5/OS that runs on the i5 servers makes it somewhat problematic to compare them to 32-bit X86 machines running Microsoft‘s Windows Server 2003 operating system and SQL Server 2000 database. For instance, the i5 software packing is split based on whether a customer wants to run 5250 green-screen protocols (Enterprise Edition) or not (Standard Edition). The full capabilities of the i5 hardware, i5/OS operating system, and DB2/400 database are available on both kinds of machines, which have wildly different prices. (Green-screen customers are still paying through the nose.) In the Microsoft world, there are many different Windows 2003 editions, which are differentiated by the number of processors they can span, the size of the main memory they can address, and certain other features. The same holds for the SQL Server 2000 database, which has an Enterprise Edition with all the bells and whistles and costs $19,999 per processor, as well as a simpler version called Standard Edition that can only span up to 2 GB of main memory. Moreover, i5/OS is licensed for an unlimited number of users; whereas Windows Server 2003 has per-user fees (called Client Access Licenses, or CALs) that customers have to buy in addition to the basic operating system license.

Perhaps most significant, OS/400 and i5/OS have excellent workload managers that allow many applications to run concurrently on a single machine, driving up use to 60 percent or higher for many customers; Windows has lacked a decent workload manager, and companies have had to break up workloads across multiple machines to isolate them, and they often see average server utilization in the range of 10 to 25 percent.

To make any comparison at all, one has to make assumptions. This is what all of you have to do as you make your platform choices, and you well know that it is an imperfect science. For the sake of comparison, I have used my estimated TPC-C transaction per minute (TPM) ratings for the new i5 servers and compared them to the actual performance ratings recently published by Hewlett-Packard for selected ProLiant servers running Windows 2003. These servers fall into roughly the same performance bands as I used last week to compare the new i5 servers to the prior iSeries servers. I have assumed that both types of machines are running full-out at peak capacity in making price/performance comparisons. I have also done my best to isolate the cost of the base server, the base operating system, and the base database in order to make comparisons fair. I want to isolate the value in the base platform on which customers then build their configurations. I do not want to let differences in memory, disk, or other feature prices skew the value inherent in the base platforms.

As the table indicates, the two smallest i5 Model 520 Express configurations, which have a 1.5 GHz Power5 processor that is geared down by about a factor of five for non-5250 workloads (and even further for 5250 workloads), are in spitting distance of an HP ProLiant DL320 server with a single Pentium 4 processor, in terms of the cost of a base system. But because IBM is seriously gearing down the performance of these boxes (which are labeled Express #1 and Express #2 in the table), the cost of a unit of work is about double that of the baby ProLiant server running Windows Server 2003 Standard Edition and SQL Server 2000 Standard Edition. There is an important thing to realize: the Standard Edition is limited to machines with 2 GB or less of memory. IBM’s i5/OS, in either Standard or Enterprise Editions, has no such limitations. Moving to SQL Server 2000 Enterprise Edition, to address more memory, would drive the cost of SQL Server 200 from $4,999 per processor to $19,999 per processor; and such a move would require a move from Windows Server 2003 Standard Edition to Enterprise Edition, which would raise the Windows price from $1,199 to $3,999. That’s an extra $17,000, which puts that Windows machine in the same price band as the Model 520 Express #3 configuration, which costs $29,900 and has about the same performance.

In other words, IBM’s i5 prices are arguably equivalent, depending on how generous you want to be with the CPU utilization and workload manager issue. (If you are trying to buy an i5 server, you would be wise to say that this will not affect your decision, since tools like VMware‘s GSX Server can isolate partitions on a Windows box. But, then again, the i5 has logical partitioning built in.

Moving up to slightly more capable machines in the 25,000 TPM power class, an i5 Model 520 with i5/OS Standard Edition can keep pace with a two-way ProLiant ML350 Xeon DP server. It has a little bit less performance but has slightly better price/performance. However, customers who need i5/OS Enterprise Edition are paying about 2.6 times as much for green-screen processing capacity. IBM has the monopoly on the 5250 protocol, and there is no way IBM is not going to charge a hefty premium for it. But IBM is on par with Windows here, and that is real progress.

For larger machines, in the 50,000 TPM and 100,000 TPM power ranges, the two- and four-way i5 Model 570s are too expensive, compared with two- and four-way alternatives using the Intel Xeon DP and MP processors. The Model 570 has a lot of sophisticated electronics and software support that will allow them to eventually scale to 16-way servers, and that is why these machines are so expensive. This is also why it would be wise for IBM to deliver a lower cost, four-way i5 Model 550 soon. IBM needs a four-way box priced like the Model 520, competitive with Windows, even without the ease of use, CPU utilization, and workload manager arguments. If IBM wants to win the hearts and minds of midrange shops, it needs to meet or beat Windows on raw price/performance for full tilt boogie machines, and then offer these benefits that the Windows platform cannot.