IBM eServer xSeries x440

IBM eServer xSeries x440

IBM has truly thought “out of the box” with its new xSeries x440 server that began shipping in April. The company has taken server scalability and processor density to a new level with the ability to run eight processors in a 4-U (7 inches) rack-mountable chassis and then connect two chassis together to create a 16-processor server. This ability to scale processors outside the chassis is a novel approach to increasing server horsepower. Because of its outstanding performance and wealth of features, we give the x440 a World Class Award.

Server description

The processors reside in a symmetric multiprocessing (SMP) expansion module that holds four Intel Xeon MP (multiprocessing) processors or two Intel Xeon DP (dual processing) processors. Two SMP expansion modules can be loaded into an x440 chassis to hold up to four Xeon DP or eight Xeon MP processors. The SMP expansion modules are common to the supported processors, so upgrading from Xeon DP to Xeon MP only requires swapping out the processors. Our x440 came with two SMP expansion modules with four 1.6-GHz Xeon MP processors in each module for a total of eight Xeon MP processors. IBM also shipped two additional SMP Expansion Modules with two 2.4-GHz Xeon DP processors each for a total of four Xeon DP processors. This four-way Xeon DP server configuration was announced Aug. 30.

Each SMP expansion module has 16 DIMM slots to house a maximum of 32G bytes using 2G-byte DIMMs. The 16 DIMM slots can be mirrored into two banks of eight slots. If a DIMM fails in the mirrored configuration, the standby memory bank will activate to reduce downtime. Hot-swap memory is not available on the x440, but is expected in a future release. The SMP expansion modules are not hot-swappable.

The x440 supports Windows 2000 Server, Advanced Server and Datacenter operating systems, along with SuSe and RedHat Linux distributions, and NetWare 6. Our x440 came loaded with Windows 2000 Advanced Server.

Performance

The x440s performance was outstanding. The Secure Sockets Layer transaction rate was impressive, and the processor scalability was nearly perfect.

In our tests of the two and four Xeon DP processors, we achieved 32 SSL transaction/sec with two processors, and 54 SSL transaction/sec with four processors. In the tests with two, four, six and eight Xeon MP processors, we achieved SSL rates of 16, 35, 50 and 70 transactions per second, respectively. The DP performance is slightly higher than the MP performance because the DP processors run at 2.4GHz and the MP processors run at 1.6GHz.

The x440 scales perfectly with each increase in processor horsepower. This is quite an achievement considering most multiprocessor machines we have tested only show an 80% increase in performance with a 100% increase in the number of processors.

Features

Because of its abundance of features, the x440 gets another perfect score. Compute scalability is the most impressive of the x440 features. As well as being able to grow from two to 16 processors, each SMP expansion module has a built-in Level-4 memory cache that can hold 32M bytes of dual data rate memory to its pool of four processors. In a 16-way configuration with four SMP expansion modules, the Level-4 cache can scale up to 128M bytes. The idea behind the Level-4 cache is to reduce the contention for main memory bus by the processors and PCI-X slots.

The six 64-bit PCI-X slots in the x440 chassis also are impressive. PCI-X is the new improved PCI specification that allows higher performance through optimized PCI bus use and higher bus bandwidth. Each PCI-X slot is hot-swappable adding to the server’s potential uptime.

The memory architecture is full of availability features. The x440 lets you correct multiple-bit memory errors through Chip-Kill technology, parity-based redundant memory called Memory ProteXion, and memory mirroring. Memory mirroring lets you install two banks of redundant memory on an SMP expansion module. If the Module detects memory errors in the active memory bank, it switches to the back-up memory bank if memory errors occur. This feature will allow the addition of hot-swap memory. Hot-swap memory is not currently available on the x440.

The x440 also can be partitioned into independent machines that can be clustered. The result would be a potential boost in uptime with a minimal effect on performance. Two x440s integrated into a 16-way configuration can be partitioned into four independent four-way machines, two independent eight-way machines or one independent 16-way machine.

The BIOS can detect and disable faulty processors to reduce downtime. Because the processors are not hot-swappable, downtime is necessary to replace a faulty processor.

In addition to hot-swap PCI-X slots and memory mirroring, the x440 has the standard list of availability features such as hot-swappable hard drives and redundant load-balancing power supplies, with a separate power cord for each power supply. The use of the Broadcom Ethernet chipset limits Ethernet network interface card failover to another Broadcom PCI NIC as opposed to the server industry standard Intel Ethernet chipset.

Serviceability

Working on the system was relatively easy but not perfect. The system fans, hard drives and power supplies can be replaced without opening the chassis cover or using tools. The cover opens easily, exposing the PCI-X slots and the topmost SMP expansion module. These expansion modules are easy to insert and remove. The cables connecting the SMP expansion modules are a little cumbersome to use. You have to remember to take them out before removing an SMP expansion module, which isn’t very intuitive. This could result in user-created hardware failures. The cables also are a little tricky to reinsert into the SMP expansion modules.

Memory is a breeze to remove and replace on the SMP expansion modules. The processors are a different story. The heat sinks are difficult to replace, and the processors are a little difficult to remove and replace from their sockets.

Manageability

The x440 comes shipped with IBM Director management software. This software provides hooks into the standard systems management platforms such as Computer Associate’s Unicenter, Hewlett Packard’s OpenView and Tivoli Systems. Director also provides a way to manage hardware components for failure and analyze the x440’s capacity. Director alerts the administrator in the event of a hardware failure or overutilization of a system resource.

The front of the server houses the Light Path Diagnostics panel to inform the administrator of any hardware failures. The Light Path Diagnostics track CPU, memory, fan, and power supply failures. Even though it is nice to have one location to summarize hardware failures, further tracking capabilities are needed to find individual failed components in the chassis.

The Remote Supervisor Adapter is a PCI card in a special slot on the system that provides remote console and text/graphics redirect, power on/off and system reset. It also monitors power status, temperature, hard drives, fans and power supplies. This card is up even if the x440 is powered down and is connected to a remote management terminal by serial connection or over the Internet by 10/100Base-T Ethernet.

Conclusion

The x440 is an impressive package of computing performance, scalability, availability and manageability. It should work well in large corporate environments where performance and future protection is important. If you are considering server consolidation, this could be the server for you.

The entry price with two 2.4GHz Xeon DP processors is a bit pricey at $20,500 – definitely not for the faint of heart. This kind of commitment at the entry configuration requires some upfront work to decide if this is the server for you. Once you are prepared to make that commitment, the x440 should grow with your needs over time in a cost-effective manner.

Server testing is performed at North Carolina State University’s Centennial Networking Labs (CNL) in Raleigh, N.C. CNL tests network equipment and network-attached devices for interoperability and performance.

Bass, a senior technical staff member at CNL and co-author of Building Cisco Multilayer Switched Networks, designs and leads the execution of the test suites. He can be reached at john_bass@ncsu

.edu. Khurram Khan, Piyush Raju and Sangram Kadam assisted with the testing.