IBM Upgrades High-End System i Server with Power6

July 24, 2007 Timothy Prickett Morgan

Mirroring what IBM‘s formerly independent System p division did back in May, the Power Systems division–the amalgam of the System p division and the high-end of the now broken up System i division, which was created last week–has announced its first product. It is the first server with the System i brand that makes use of the dual-core Power6 processor. The machine bears a strong resemblance to the rejiggered System p 570 that Big Blue announced back in May.

While IBM may have split the System i division into two pieces, one that merged with its AIX and Linux machines and another, called the Business Systems division, which aims to promote entry and midrange Power-based servers running i5/OS to small and medium businesses, the System i brand will live on as its own entity. At least for now. It would not be surprising for IBM to eventually come to the conclusion that it is easier and smarter to just sell machines called Power Systems, and tout the fact that they run i5/OS, AIX, and Linux equally well. Hewlett-Packard does this with its Integrity Itanium-based server line, which supports HP-UX, Windows, Linux, OpenVMS, and the NonStop kernel. Unisys is also moving in that direction as it converges its ClearPath mainframe and ES7000 X64 and Itanium server lines.

Since last fall, IBM has been a little vague about its product plans for the System i line, and did not commit to delivering Power6-based machines to the line. In fact, late last year executives in the System i division attempted to put the kibosh on talk of Power6 machines, and said that maybe the next release of the operating system, which was called i5/OS V5R5 at the time, might see the light of day in late 2007. Earlier this year, as details began to emerge on IBM’s Power6-based servers, it became clear that the System p line would get Power6 first. Soon after the updated System p 570 server, which spans from two to 16 cores, was launched in May, there were some rumors that this machine would come out with a System i label before the end of the year, not in early 2008. IBM’s high-end server customers who have invested in the System p and System i 570 machines apparently made it clear that they wanted machines with more oomph, or else IBM would have put Power6 chips elsewhere in the lineup first.

Rather than launch Power6-based machines in April with a new user-based pricing method, the company created the System i 515 and 525 entry servers, which are based on existing Power5+ chips. These chips supply plenty of performance for entry i5/OS customers and leave enough headroom for a partition or two running AIX or Linux, if customers decide they want to run some infrastructure workloads on the boxes. And rather than wait for the true Power6 servers–which I wrote about back in April–IBM has decided to offer customers the same rejiggered 570-class box, which was tweaked to run the Power6 chip instead of the Power5 and Power5+ chips it was sold with originally. IBM had to backcast AIX 5.3 to run on this machine, which does not support all of the features of the Power6 chip, and similarly, i5/OS V5R4 has been tweaked to become V5R4M5 so it can run on the modified System i 570 with the Power6 chip and other features inside the box, such as Serial Attached SCSI (SAS) drives and a new I/O interconnect based on InfiniBand called 12X.

The heart of the new machine, of course, is the Power6 processor, which is implemented in a 65 nanometer chip process and which has 790 million transistors on it–about three times that of the Power5+ chip. That’s a lot more transistors to cram into the same thermal envelope as the Power5+ chip, and IBM has added a lot of features to the Power6 to make it appealing to customers. First and foremost is clock speed. The System p 570 is using Power6 chips running at 3.5 GHz, 4.2 GHz, and 4.7 GHz, while the System i 570 will only take the fastest part. (The System i 570 using Power5+ chips also got the fastest 2.2 GHz parts only.) Each Power6 core has simultaneous multithreading (SMT) electronics on it, and rather than shrink the length of the instruction pipeline as the clock speed was increased, IBM’s chip engineers figured out ways for the pipeline to stay the same length and become more efficient, allowing the clock speed to be doubled from the Power5 design. Each Power6 has 8 MB of L2 cache memory (4 MB for each core) on the chip and the design allows for 32 MB of off-chip but on-package L3 cache memory to be added to each Power6 module. Main memory and L2 cache memory controllers are also embedded on the chip. Each core has a VMX vector processor math unit, which will make the Power6 very fast at floating point math. A decimal floating point unit, which does base 10 or “money” math, was also added to the Power6–the first such one in the chip industry–and it can speed up decimal math operations by a factor of 2 to 7 according to IBM’s initial tests.

The System i 570 with the Power6 processor can host up to 768 GB of main memory using 400 MHz DDR2 DIMMs; if it is like the System p variant of this machine, customers can add faster 533 MHz or 667 MHz main memory, but doing so cuts the main memory capacity in half for each speed bump. (That’s 384 GB and 192 GB.) Like the System p version of this machine, the System i version comes with SAS disk drives, which have performance benefits compared to Ultra320 SCSI disks. IBM is not, however, supporting small form factor SAS drives in this machine. Up to 387 TB of disk capacity can be attached to this modified System i 570, using either the existing HSL-2 I/O interconnect or the new 12X I/O interconnect. Like prior System i 570 machines, the system is comprised of one to four chasses, each with up to two dual-core processors, which are connected in a single system image through special fibre optic cables. Each chassis in the new System i 570 configuration has room for six 3.5-inch SAS drives, which are supported in 70 GB, 140 GB, and 284 GB capacities and which spin at 15K RPM. The initial configuration comes with six drives mirrored, since IBM likes mirroring better than RAID 5 or RAID 6. Each chassis in a System p 570 and System i 570 server has four PCI-Express 8x slots and two PCI-X slots.

In terms of performance, the new Power6-based server provides a different speed bump depending on the test. (More on that in next week’s issue of The Four Hundred. Based on its Commercial Performance Workload (CPW) benchmark test, which IBM uses to gauge the relative performance of AS/400, iSeries, and System i machines and upgrades between them, a top-end System i 570 machine with 16 Power6 cores running at 4.7 GHz is rated at 76,900 CPWs, an increase of 72 percent over a 1.65 GHz Power5 machine from four years ago and up 31 percent from last year’s Power5+ box. The Power6 server has nearly four times the oomph of the Power4-based machine with 16 cores from 2001.

Perhaps the most interesting thing about the System i 570 is that it only comes with one variant of the i5/OS operating system. IBM has smartly done away with Standard Edition, which cannot support the 5250 green-screen protocol commonly used by RPG and COBOL applications on the i5/OS and OS/400 platform, and i5/OS Enterprise Edition, which has full 5250 capability. You just get i5/OS by the core, and it includes DB2/400 integrated. What it does not include are many of the extra features that were thrown in with i5/OS Enterprise Edition on the Power5 and Power5+ System i 570 machines of years gone by. These are going to be sold as “value packs” for i5/OS.

IBM is also packing the chasses slightly differently with the Power6 version of the machine, offering machines that span from 1 to 4 cores, from 2 to 8 cores, and from 4 to 16 cores. The past System i 570s ranged from 2 to 4 cores, 4 to 8 cores, and 8 to 16 cores, and the two highest bumps required a change from the P30 software tier of the entry machine to the P40 tier. This, obviously, upset many System i customers, since adding more processors to run AIX or Linux would push them into a higher software tier on their core applications. Now, a System i 570 machine with a Power6 chip has one tier–P30–no matter what the cores are being used for.

At $165,000 with one core activated to run i5/OS, the entry Power6-based System i 570 is a bit more expensive than last year’s i5 570 running i5/OS Standard Edition, which cost $145,000. But maintenance prices have been chopped in half, and you only buy the software features that you use on this new machine. It costs $17,700 to activate a Power6 core in this box (up from $10,500 for a Power5+ core). It costs $59,000 to license i5/OS on an activated core and another $50,000 for the Enterprise Enablement feature that supplies 5250 green-screen transaction processing. If you want to run applications like WebSphere on an i5/OS core, you can license i5/OS Application Server for $19,000. This app server variant of i5/OS, which does not include DB2/400, was announced back in April to make it more attractive to run WebSphere on i5/OS natively. The base 2/8-way System i 570 with the Power6 chip costs $220,000, the same as the Power5+ 4/8-way box, while the 4/16-way variant costs $340,000, down from the $380,000 IBM was charging for the 8/16-way box.

The new Power6-based machine will be available on September 14.

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