IBM Cranks the Clock on Power, Xeon Blade Servers

by Timothy Prickett Morgan

IBM last week finally delivered its AIX variant of the Unix operating system on the PowerPC-based blades inside its BladeCenter chassis. In addition, the company is boosting the performance of those PowerPC blades, which can also run Linux, and rolling out new X86-style blades based on Intel's "Nocona" 64-bit extended Xeon processors with 800 MHz front side buses.

The new JS20 blade server is based on a 64-bit PowerPC 970 processor, but this one runs at 2.2 GHz instead of 1.6 GHz. The JS20 blade comes with 512MB of main memory and two 2.2GHz PowerPC 970 processors (you can't buy just one). The updated PowerPC 970 sports a 1.1 GHz frontside bus, compared to an 800 MHz frontside bus in the 1.6 GHz variant of the chip. (In the Power architecture, frontside buses run at half core processor speed; in the Intel architecture, frontside buses are set with each iteration of the chip and clock speeds vary as a multiple of that bus speed). Tim Dougherty, director of BladeCenter marketing at IBM, says that the company is charging the same $2,699 for the new blade--which has a 30 percent faster clock speed but which can deliver 50 percent more computing power on many workloads because of the faster bus speed--as it charged on the old blade. IBM has also cut the price of the two-way 1.6 GHz JS20 blade by 20 percent to $2,159. These PowerPC blades use IDE disk drives, which cost $299 in a 40 GB capacity.

The JS20 blades have supported Linux since they were announced in November 2003 and started shipping in June after a three-month delay related to some memory issues on the blades. With last week's announcement, IBM is shipping AIX 5.2, its prior release of Unix, on the JS20s, and Dougherty says that IBM will ship AIX 5.3, the latest version, by the end of the year. The JS20 blades are interesting for IBM Unix customers specifically because the PowerPC 970 processors support the VMX vector processing functions that debuted in Motorola variants of the PowerPC designs and that Apple makes use of in its workstations and servers. VMX can significantly boost floating point calculations, offering as much as a factor of two or three performance boost on such operations compared to a PowerPC chip without them. The IBM XL C/C++ Advanced Edition V7.0 and XL Fortran Advanced Edition V9.1 compilers for AIX already could take advantage of these VMX functions (which are not in the Power4 and Power5 designs, ironically), and with last week's announcements, the Linux versions of these compilers can make use of the VMX instructions. What the JS20 blades cannot support are the dynamical logical partitioning features of the other IBM 64-bit PowerPC "Star" family, Power4, or Power5 processors (the PowerPC 970s lack the electronics and microcode to do so). These virtualization features may not be as necessary for blade environments as they are for monolithic servers, since customers think of and use blade servers and server partitions in much the same way. The new JS20 blades will be available worldwide on October 29.

On the Nocona front, IBM is offering HS20 blades, which have been tweaked to support the new Xeon-64 chip and have had their server components rearranged to make them more useful. IBM is offering the HS20 with Xeon-64 chips ranging in speed from 2.8 GHz to 3.6 GHz. This is a significant boost in processing capacity, and the blades will obviously be able to address a lot more memory. IBM had been shipping HS20 blades with Xeon chips with 533 MHz frontside buses, but with the Noconas, the bus speed has been cranked to 800 MHz. As was the case with the PowerPC blades, the boost in bus speed along with faster clocks will help these machines do a lot more work, as will the 64-bit support for some workloads.

The interesting bit of news with the HS20 blades is that IBM has rejiggered the blade boards so the internal disk drives and daughter cards that allow for Ethernet and Fibre Channel connections are not jockeying for space. With the new design, customers can put two disk drives on a blade and also put in two communications cards. Part of the reason IBM could do this is that the new HS20 blades with the Xeon-64 chips use 2.5-inch SCSI disk drives rather than the 3.5-inch IDE drives used previously. IBM is offering the 2.5-inch disks in 36 GB or 73 GB capacities and at 10K RPM. Prior to this announcement, customers who wanted more reliable SCSI disks for their blades had to lash an expansion chassis to the blade, which ate up an adjacent blade slot to provide support for two SCSI disks. Customers can now use that expansion chassis to house two more 2.5-inch disks and provide RAID 1 mirroring across four striped drives, or to plug into two more communications daughter cards, boosting the connectivity of a single blade to a maximum of eight Gigabit Ethernet ports or four Fibre Channel ports.

An HS20 blade with a single 2.8 GHz Nocona chip, 512 MB of disk, and no disk costs $2,039; a 36 GB disk costs $399. Dougherty says that IBM will drop the prices on prior generations of Xeon-based blade servers, but the details of those price cuts were not available as we went to press.

In addition to the new hardware, IBM has enhanced the UpdateXpress feature of its IBM Director blade management program so that it can examine the network infrastructure within a blade configuration and flash the BIOS and other software associated with these devices. It works with the network switching equipment from Nortel Networks, QLogic, Brocade, and Cisco Systems that IBM has endorsed for the BladeCenters. This iteration of IBM Director with the network-enabled UpdateXpress will ship for Windows next week and for Linux by the end of the year. (IBM Director has to run somewhere on the blade setup.) The software already provides BIOS flashes and operating system patching for all of IBM's blade servers.

Dougherty also says that IBM is introducing another feature in the BladeCenters called PowerExecutive, which is a function of the service processors that run in the BladeCenter chassis. This software monitors the power consumption of the components of a blade chassis and can, on the X86 blades, reach in and access the SpeedStep features of Intel's latest chips and crank down the clock cycles on the processors to reduce their power consumption if they are not actively processing a lot of data. Similar power stepping features are expected in the PowerPC blades at some point in the future. PowerExecutive can also step down the power on redundant components, such as power supplies and fans, which may not be necessary on a machine that has been dialed back. In the event that a primary component begins to fail, PowerExecutive can crank the redundant component up to full speed so it is ready to take over.