IBM Builds on Block Servers

IBM rolls out 16-way modular servers

• By Chris McConnell
• 03/13/2002

Compared to Unisys’ ES/7000, which packs as many as 32 processors into a cabinet-style unit, IBM takes a different approach to create a scalable, partition-able Intel server. Big Blue chose to use rack-mountable units using proprietary interconnects to scale processors and I/O. For partitioning, the servers use either hardware partitioning or virtual, software-based partitions. IBM believes this approach gives users more flexibility than a monolithic server.

The new server is available in 2-to-16 way configurations. Up to eight Xeon MP processors can fit in a 4U chassis, and two chassis can be tied together with a proprietary “scalability port” which enables it to scale to 16 processors. IBM developed its own chipset to achieve this scalability.

The eServer x440 follows IBM’s shipment of the x360 late last year. The 4-way x360 gives enterprises the ability to add I/O through scalability blocks which reside in a separate 3U chassis. x440 can also add 6 PCI-X slots with one of these chassis. x360 can not scale-up processors like the x440.

IBM’s latest server shares characteristics with an older member of the IBM server family. Like IBM’s NUMA-Q servers, processors are interconnected via an external memory cache, in this case an L4 cache, allowing the chips to trade data at a high speed. The scalability port, which connects the two server chassis for scaling, connects to the L4 cache, so the wire speed is about equal to the speed of the memory controller.

“The NUMA-Q brand was helpful in putting the architecture together,” says Jay Bretzmann, manager of high-performance product marketing at IBM. Bretzmann says IBM also leveraged some technologies in IBM pSeries line of Unix server in this design.

Although NUMA-Q has taken a lower profile in IBM’s server lineup, Bretzmann says IBM will continue to update the non-uniform memory architecture servers through this, and perhaps next, year. IBM recently releases kernel enhancements for the NUMA-Q series that allow Linux to run on the architecture.

x440 can be partitioned in two ways. Administrators can create up to two hardware partitions by using independent chassis. Software from VMWare Inc. is also available to create up to 64 software partitions.

Today, software partitions are somewhat distinct from virtual partitions on the mainframe. They can scale up to one processor, so an eight-way server must run a minimum of eight partitions. Bretzmann says IBM is collaborating with VMWare to extend the software to support 2-and-4-way partitions in the near term.

Bretzmann says that VMWare’s virtual partitions make a compelling case for using x440 as a consolidation platform. Multiple file-and-print or other irregularly used servers can be moved onto a single server, reducing hardware and support costs. “It gives back capacity you’ve already bought,” he says.

IBM also positions x440 as a platform for running e-business applications such as PeopleSoft or SAP and notes some businesses may be interested in using it as a back-end server. “We think this is a database-capable backend server,” Bretzmann says.

When x440 reaches the market this summer, Bretzmann expects IBM to offer it primarily for Windows and Linux.