Everything about the IBM BladeCenter H just screams IBM, from the mainframe-like aesthetics to the spartan management interface -- even the "H" model name. Severe-looking matte-black chassis notwithstanding, the BladeCenter H matches most of the major features of the Dell and HP blade systems but at a higher price. The BladeCenter also comes in smaller portions: IBM's slightly shorter chassis holds fewer blades than the Dell and HP enclosures.
With features like the Virtual Fabric virtualized network I/O, the HS22V blades specifically designed for virtualization, and reasonably complete embedded management tools, the BladeCenter H is a solid solution. But the higher price, lower density, and lack of advanced embedded management capabilities are drawbacks.
Chassis and blades
The IBM BladeCenter H is a 9U chassis that holds 14 blades -- again, 2 fewer than the HP and Dell blade units. Each blade is surprisingly slim, but they're otherwise nearly identical to the others' blade offerings. There's no heads-up LCD, and several of the status lights are small enough to be difficult to see at a glance. The H chassis is also unique in having a vertical DVD-ROM drive set into the bezel on the right-hand side; each blade has a Media Tray button that maps the contents of that drive (or an image via the management console) to that particular blade.
In the rear, there are eight I/O slots, split into two groups of four. The four traditional modules support lower-bandwidth I/O, including gigabit Ethernet and 1x InfiniBand or Myrinet fabrics. The other four modules are tasked for high-bandwidth I/O, including 10G Ethernet and 4x InfiniBand. As with the others, they're mapped 1-to-1 to the blade I/O ports, so you'll need a matched set of I/O modules in the rear to fully support the internal I/O in each blade.
The internal I/O of each blade is more like Dell's than HP's: The gigabit Ethernet interfaces are embedded on each blade, and 10G interfaces are supplied on a mezzanine card. However, like HP, IBM includes a virtual interconnect: IBM's Virtual Fabric for 10G interfaces represents a 10G pipe to a blade as four Ethernet ports that can each be tuned for specific functions or bandwidth caps. Like the HP equivalent, configuring the Virtual Fabric modules is nothing like configuring normal switches, and the IBM techs didn't really know how it worked. We couldn't even get into the configuration for those modules to poke around.