How Far Will IBM Push Linux on Power5 Squadrons?

by Timothy Prickett Morgan

IBM started shipping its first two Power5-based "Squadron" servers last week. The eServer i5s, as its first Power5 machines are called, support OS/400 and Linux within logical partitions on the same box; in the fall, they will support AIX, too. With such a heavy emphasis on Linux these days, it seems likely that IBM will debut a version of the Squadrons that just run Linux. IBM has given no indication it will do this, but it makes sense.

As we have previously reported, IBM has announced a two-way Model 520 and a four-way Model 570 in the new eServer i5 (formerly iSeries) midrange server line. IBM is expected to launch a line of Unix-based kickers to the pSeries line, dubbed the p5, using these two chassis; Linux partitions are expected to be available on these machines too. But what about customers who want a Squadron box to run Linux and only Linux? Such customers will not spend the substantial money for a license to OS/400 (which is now called i5/OS), and they do not want to pay for AIX even if the base license is not that expensive.

Linux, particularly with the new Linux 2.6 kernel, is not a limitation. Novell's SuSE Linux Enterprise Server 9, which is due later this summer for commercial distribution, has been demonstrated running on a 32-way NEC "Asama" Express5800 1000 series server, and scaling almost as well as Unix environments that are a decade older and highly tuned. Even the enhanced Linux 2.4 kernel that Red Hat created as Linux Enterprise 3 can scale to 16 processors in a single system image. As long as applications can be tweaked to take advantage of SMP and NUMA scaling and the substantial increase in the number of threads supported by the Linux operating system, Linux is not the issue for 99 percent of the application workloads out there. And for those who need greater scalability, there are means to cluster databases for horizontal performance.

IBM has some interesting options in creating a full line of scalable Linux servers. IBM's top brass has confirmed in several meetings with Guild Companies that the company is indeed trying to get the high-end 64-way Squadron box, presumably to be called the Model 590, out the door sometime in 2004. As I suggested in the past it might, IBM appears to be trying to synchronize the iSeries and pSeries launch of this big bad box. Shipments of this machine and AIX 5L 5.3, which is required for the Power5 machines, are not expected until late September or early October, but the rumblings I hear are that IBM might launch the machine in late July or early August, to give its sales team some time to crank up the sales cycle so IBM will enter the fourth quarter with a lot of momentum. Given the limits of Linux scalability, it seems unlikely that IBM will announce a 64-way Linux-only box. But it could put two Linux partitions on such a machine and deliver that as a giant database server; and even if it does not announce such a box, Big Blue will certainly be able to and will be thrilled to build such a monster Linux box on a special-bid basis.

IBM is also reportedly working on a four-way Squadron server, which will be called the Model 550. It will slide into the product line between the new Model 520 (which has up to two 1.5 GHz or 1.65 GHz Power5 cores activated) and the Model 570, which can have up to four of the 1.65 GHz cores. The Model 570 is more than a simple four-way server, as the Model 550 is expected to be. The Model 570s include sophisticated NUMA-like clustering technologies built right into the system board that will allow two, three, or four Model 570 systems to be glued into a single system image that spans from one to 16 active processor cores. This is very similar to the xSeries 440 and xSeries 445 "Summit" servers IBM sells using Intel's Xeon and Itanium processors. The Model 550 is important because the Workgroup Edition of Oracle's eponymous databases is only available on machines that top out at four active processors or cores. Any machine that can scale beyond four-way processing has to run Oracle's Enterprise Edition, which costs a lot more money. Having a four-way Power-Linux box like the Model 550 is going to be a key requirement if IBM wants to sell Linux clusters to support HPC and clustered database workloads.

The NUMA-style clustering technologies are not cheap, however, and IBM eventually wants to have a workhorse but inexpensive four-way server to fill in the gap between the Model 520 and the Model 570, just like it does in the current xSeries. The odds are that IBM will offer an upgrade path from the Model 520 to the Model 550 as well, which gives entry customers somewhere to go when they outgrow their machines. It is unclear when IBM might launch the Model 550, but it could be announced around the same time as the Model 590 or it could come out as the year ends. What IBM sources have told me is that we should expect server announcements on a more or less quarterly basis as IBM rolls out new products. IBM finally understands that people like new technology, even if they don't technically need it. Being new and exciting makes people excited.

Based on intuition, and the fact that IBM can't repeat model numbers or it will drive its pricing and configuration databases nuts, it seems unlikely that IBM will deliver i5 Model 500, Model 510, or Model 530 servers. Those are the names of the first-generation PowerPC servers in the AS/400 line, the "Cobra4" and "Muskie" 64-bit PowerPCs, which saved IBM's cookies in the midrange back in the mid-1990s. But there is room for a Model 580, which could be a future 32-way server made in the same style as the Model 570, but from server building blocks with four Power5 processors (and eight cores), instead of the two dual-core Power5s used in the Model 570.