If we had to use one word to describe Cubix's Density server, it would be solid. From the design of the chassis to the circuit and board layout, Cubix's years of experience building these systems shows. With each unit measuring slightly more than a foot high, five chassis can fit in a standard rack. In addition, a maximum of seven uniprocessor servers can be housed by a single chassis. The chassis features a magnetic faceplate that, when removed, provides access to the hot-swappable drive bays. To provide access to the insides of the box, it would have to be mounted on slide-out rails. The only significant security feature missing is a way to physically lock down the faceplate.

The Density System had the best management features of the products we tested. Our assessment of each server's management capabilities took into account not only internal management, but also the multiplexing method used to access each of the servers in the boxes. Switching between servers couldn't have been easier. Two rows of LEDs, with a corresponding number to the right, function as the server selector and the CD-ROM selector. Cycling through the server and CD-ROM is accomplished using an up or down button. Switching between chassis is done with the third button on the front panel. New to the Cubix server is the shared CD-ROM that is now hardwired.

Each chassis comes with its own floppy drive. However, the drive cannot be independently switched between serv-ers; it defaults to the server selected. Cubix uses what it calls a "breakout box" to perform multiplexing of the keyboard, mouse and monitor. If the servers are chained together in a rack, the breakout box can be used, when needed, for each separate system. There is no set limit to the number of chassis that can be connected in this fashion. This method of multiplexing proved to be the most effective and efficient way to switch between servers and chassis.

Internal management is accomplished through Cubix's Global Vision software and the IES (Intelligent Environmental Sensor). The IES monitors the internal environment while the Global Vision keeps tab on the other servers. This management combo stood out in our testing for several reasons. First, it's easy to install. We were ready to go in less than five minutes. The user interface also is very simple. A red or green dot appears to the left of the icon representing the chassis. A red dot indicates a problem.

Global Vision provides an impressive level of detail. For example, it shows internal and external temperature as well as voltage. And it gives a number of hardware statuses, including that of the power supplies and fans. On a per-server basis it gives the IP address, the currently logged user, and the duration logged in to the operating system.

One of Global Vision's most important attributes is its support of SNMP traps, which makes it possible to install the Global Vision software on any number of servers on the network. A bonus is that Cubix doesn't set any license limits governing how many different machines can be running the console.

Our tests showed the Density System 1000's performance to be acceptable but not great. However, Cubix has a 333-MHz Xeon overdrive chip for the Pentium Pros that gives it the highest possible horsepower in the roundup. Striving for reliability over bleeding-edge performance, Cubix provided us with a chassis containing four dual Pentium Pro servers. The Cubix system can be any number of mixed-and-matched CPU configurations within a chassis. However, ours was at maximum capacity with the four dual Pentium Pros because of a lack of space within the chassis. Each server in the chassis has its own PCI slot for expansion. The chassis features 10 hot-swappable drive bays as well as three hot-swappable power supplies. We gave one drive a firm tug, waited and then popped it back in. We were up again without any system lockups on any of the servers. The server blades within the chassis are also hot-swappable.

Fault tolerance is provided via an N+1 power supply with three load-balancing power supplies. A few seconds after pulling the power on one of the supplies, we were greeted by a continuous series of system beeps. With two of the three power supplies still working, all servers were behaved normally. We were happy to see a dual port 10/100 NIC in each of the servers for port aggregation and fail-over.