The Linux Beacon--IBM Announces Improved X64 and Cell Blade Servers

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Volume 5, Number 20 -- May 20, 2008

IBM Announces Improved X64 and Cell Blade Servers

Published: May 20, 2008

by Timothy Prickett Morgan

IBM has revamped its line of X64 and Cell blade servers, pushing the envelopes on raw performance and performance per watt in an effort to serve what have become two distinct customer needs.

Last week, IBM announced two new X64 blades, the HS21 and HS21 XM, the latter being short for Extended Memory. The HS21 is a single-wide, full height blade based on the low-voltage variant of Intel's latest "Penryn" Xeon, the L5240, to be specific. This chip clocks in at 3 GHz but has a thermal design point (TDP) of only 40 watts. It has a 3 MB L2 cache per core on the Xeon die and a 1.3 GHz front side bus. The updated HS21 blade has two processor sockets (for a total of four cores per blade) and room for two SAS drives (they are not hot swappable) and up to 16 GB of main memory. However, the HS21 also has a memory and I/O expansion blade option, which puts more disks, I/O slots, and memory slots on a processor-less blade beside the HS21 blade that allows it to double all of its capacities excepting computing. The HS21 XM blade uses faster and hotter 667 MHz DDR2 main memory and has only one disk slot, which can use a SAS drive or a 15.8 GB or 31.4 GB solid state SATA memory drive. The HS21 XM blade also has space for a 4 GB or 8 GB modular flash drives that hook into the blade through USB ports. The HS21 XM uses the same Xeon L5240 processor, and costs $2,855, while the regular HS21 blade using the L5240 chip costs $2,995. Both blades already support regular voltage dual-core and quad-core Xeons as well as a number of slower low-voltage Xeons.

Both X64-based blades are certified to run Red Hat Enterprise Linux 4 and 5, Novell SUSE Linux Enterprise Server 9 and 10 and NetWare 6.5 with Service Pack 5, and Microsoft Windows Server 2003. VMware's ESX Server 3.0.1 hypervisor is also certified on the machines. Windows Server 2008, the latest operating system from Microsoft, is not yet certified on the machines.

IBM is continuing to make improvements to its Cell-based blade servers, and last week the company switched from a relatively skinny complement of Rambus XDR main memory to a more standard and capacious set of DDR2 main memory. The original QS20 blade had only 512 MB of XDR memory when it was launched in September 2006, and the QS21 blade that debuted a year later had 1 GB of main memory plus two InfiniBand ports on the blade, making it much more appealing to supercomputer cluster buyers and more useful as an adjunct number-crunching node for general purpose machines. The QS20 blade had two Cell chips running at 3.2 GHz and took up two slots in a BladeCenter chassis, while the QS20 put the same two Cell processors and the other electronics in a single-wide blade. This allowed IBM to double the aggregate processing capacity of a rack of Cell machines to 25.8 teraflops per rack.

With the QS22 blade, IBM has the same two Cell processors on the blade, but it is using the PowerXCell 8i variant of the chip, which has five times the double-precision floating point processing power (217 gigaflops per blade) of the QS20 and QS21 blades. (Single precision performance of 460 gigaflops is the same for all three blades.) The QS22 has two Gigabit Ethernet ports on the blade, with InfiniBand links being made an option through daughter cards. The blade also supports up to 32 GB of 800 MHz DDR2 main memory and larger I/O buffers to keep the Ethernet and InfiniBand links from flooding the processors. With the change in processor, the double-precision performance of a rack of QS22 blades now weighs in at 12.2 teraflops. The QS22 blade can only be used in IBM's high-end BladeCenter H chassis.

The QS22 blade server will be available on June 6, and support Red Hat Enterprise Linux 5.2, which is not available yet but which almost certainly will be announced at the Red Hat Summit in Boston in the middle of June. A base QS22 blade with 8 GB of memory and two Cell chips costs $9,995.