If you are looking for lots of server power packed into a small space, look no further than the IBM xServer 336 series. In our tests, we were impressed with its solid performance, a great physical design and management features.

The server's single-rack space form will be attractive for enterprise applications where two-processor servers are needed yet space is a premium. For example, businesses with many CPU-intensive Web and database applications that require dedicated servers would benefit from the x336.

The server packs two 3.6GHz processors, two PCI-X slots (we had one 64-bit 133-MHz slot and one 64-bit 100-MHz slot), two Gigabit ports and two 3.5-inch drive slots in one 1.75-inch vertical rack space. The server we tested also included 4GB of 400MHz DDR2 synchronous RAM.

In the test, we could saturate the dual Gigabit Ethernet interfaces with 1.96G bit/sec of traffic. The server performed well, supporting nearly 760 SSL transactions per second. In our I/O subsystem test, the x336 could support 102 transactions per second, with an average disk queue length greater than five. Comparing this with other servers, our 1-year-old server could sustain only 45 transactions per second. (Note: Results are for relative performance only, not to determine absolute server load capacity. Our results can show whether one server is more powerful than another. They can't show how many users can be serviced, since the test methodology may not simulate the application used.)

Finding errors quickly
We were impressed with the system's "light path diagnostic" troubleshooting aid, which made fixing failed components fast and easy. When the retractable operator information panel extends from the chassis, LEDs become visible, indicating whether the server subsystem is the source of a system error. A "remind" button lets the user acknowledge the system error, which clears the error LEDs and causes the system-error LED on the front panel to blink every two seconds until the error is cleared. If a new error occurs, the front system-error LED panel lights up. The error LEDs indicate individual components in an error state. For example, if a RAM module fails, the system-error LED lights. After you extend the information panel, the MEM error LED light is visible. After opening the chassis, a lit LED beside the failed RAM module indicates the problem.

Under the hood
After opening the large removable cover (the cover is easy to remove, but it takes some effort to close, as it tends to get hung up in the fan access doors), the system's processors, RAM, PCI-X slots and component error LEDs are revealed. The components were neatly laid out, with no cables to route or get bound in the chassis cover. Two hinged doors on the top of the server provide access to redundant fans, which can be hot swapped in case of failure. Early dual-processor single-rack space servers (regardless of vendor) had a cooling problem, and it appears that IBM has done a good job in addressing this issue.

The back of the chassis houses two hot-swappable, load-balancing power supplies, a serial port, VGA port, two USB 2.0 ports, mouse and keyboard port, the two Gigabit Ethernet ports, a 10/100 management Ethernet port and card edges for the two PCI-X slots. The power supplies were easy to remove and replace. If using two power supplies, the two share the load, and if one fails, the server can continue to run off the lone supply.

Managing the server
IBM's Director Version 4.21 is used to manage its server line. The server and console portion is installed on the server used to manage the other servers, and the agent portion gets installed on the server being managed. Linux and Windows versions of the IBM Director components are available.

The management server is very powerful, but this comes with a cost. The server and console components are rather large and take some time to install. If you have only one or two IBM servers to manage, this might seem like too much overhead. Unfortunately, there doesn't seem to be a solution (such as an IBM Director Lite). Other than that, the Director application gave us what we'd expect from a single-vendor, enterprise-class server management platform. It let us configure, monitor, deploy and troubleshoot the x336.

The x336 system documentation was clear and easy to read. It was refreshing to quickly search a document for the necessary information and not end up following a circle of meaningless information or references to multiple sources.

The x336 is a solid-performing server, with great physical design and management features. Its single-rack space design will attract companies looking to host applications that need dual processors, but in a small space.

How we did it
Tests were executed with Spirent's Avalanche 2500 (operating system Version 62112, product Version 6.51, two CPUs) and Avalanche Commander v6.51 Build 34500.

The server under test included IIS on Windows Server 2003. All IIS logging was disabled to increase Web performance.

We ran three tests to focus on the three main subsystems of the server: CPU performance, network adapter and disk I/O. The CPU test consists of SSL transactions triggered by HTTPS requests for small files, about 1K byte in size. The goal was to load down the CPU down with SSL encryption key calculations. The small file request reduced the load on the disk I/O and network subsystems.

The disk I/O subsystem test submitted random HTTP requests of small files in a large file space. The file space (dataset) size was ideally more than four times the amount of physical memory to minimise the effects of caching. The small file requests minimised the workload on the network subsystem. The HTTP requests minimised the load on the CPU subsystem.

The network subsystem test executed HTTP requests of 35MB files. The goal of this test is to fully utilize the available bandwidth of the server.


The x336 is a solid-performing server, with great physical design and management features. Its single-rack space design will attract companies looking to host applications that need dual processors, but in a small space.