Exclusive: BladeFrame EX slices, dices, dazzles

What happens when you take a blade chassis and remove the disk, NICs, HBAs, and state from the blades? You get the Egenera BladeFrame EX. At first glance, the BladeFrame EX appears to be a standard datacenter rack populated with 1U servers, and a few larger units near the middle. When you take a peek around the back, however, there’s no nest of Ethernet, FC (Fibre Channel), KVM, and power cables; and there are only a few Ethernet and fiber-optic cables coming from the front of the rack. So what gives?

Egenera has taken a unique approach to the concept of adaptive computing. Rather than pushing images around to physical servers to achieve server mobility, the BladeFrame EX is populated with blades that have no local disk and no server state. These blades are nothing more than CPUs, RAM, and cooling fans. All the disk and network I/O is handled by central switching modules, and the server instances that run on these stateless blades are managed by central controllers. Scalent’s Virtual Operating Environment is similar to the BladeFrame EX in function, but it’s a software-only solution.

Egenera’s history dates back to 2000, with the first-generation hardware released in 2001. In the meantime, the company has found significant traction in the banking, health care, and government markets, as well as installations in the private sector. If you’ve ever used MapQuest, you’ve used a BladeFrame, albeit from the other side.

The BladeFrame EX is built into a 42U chassis, but the maximum population is 24 1U blades, although these blades are available with two or four CPUs of AMD Opteron or Intel Xeon flavors. Maxed out, a single BladeFrame EX can house 96 CPUs and 768GB of RAM. Sitting in the middle are the Control Blades and the Switch Blades. The Control Blades are essentially 4U servers with multiple high-speed I/O connections: four 2 Gigabit FC SAN ports, four fiber Gigabit Ethernet ports, and four copper Gigabit Ethernet ports. These ports comprise all of the rack’s external I/O capabilities, and they are duplicated on the second Control Blade for redundancy. The Control Blades function in an active/active fail-over configuration, so a total of 16 gigabits of external network I/O and eight 2 Gigabit FC connections are available, assuming that both Control Blades are online.

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The Switch Blades handle all internal I/O for the entire chassis, which includes internal virtual switches, connections to the SAN, and all backplane communications. The BladeFrame has no internal storage other than small disks residing in the Control Blades, so all storage is delivered from an external FC SAN.

Making it real

The key to making this solution work is Egenera’s PAN (Processor Area Network) concept, which encapsulates Egenera’s stateless approach to server hardware. Building servers on the Egenera platform is similar to building normal servers; installation media is used to install an OS to a disk, and that disk is then booted to bring the server online. However, to make that server stateless, there are a few different methods in the middle.