As for the tray fans and power supplies, well, they're not necessary. The CloudRack C2 cabinet takes care of the cooling and power distribution for the trays. That translates to fewer moving parts; this, in turn, means greater energy efficiency, fewer rotational vibrations (which can cause reliability problems), and fewer points of failure. In fact, it equals zero moving parts at the server level if you opt for SSD (solid-state disk) drives.
Opening the cabinet
The cabinet, which comes in either a 23U or a 46U configuration, boasts what Rackable calls its Power XE power-distribution technology, which the company claims virtually eliminates the problem of stranded power in datacenters. "Stranded power" refers to power capacity that is paid for but ultimately unused by IT loads due to design or system configuration. For example, say 700 watts of power is allocated to a server that only consumes around 350 watts. Those extra 350 watts of stranded power represent wasted electricity that could be put to use elsewhere. The CloudRack C2 accomplishes this feat through greater-than-95 percent phase balancing.
Moreover, the CloudRack's Power XE technology improves power-delivery efficiency by converting incoming AC power to 99 percent efficient 12V DC power via hot-pluggable, N+1 redundant rectifiers, thus eliminating the need for the aforementioned server-level power supplies. "By replacing 40 power supplies in 40 trays with six rectifiers, we have reduced points of failure," said Atashie.
In the previous version of the CloudRack, AC power was distributed directly to the trays. This new approach of using rectifiers, according to Atashie, helps address the problem of phase imbalance and stranded power.
As for cooling, the cabinet has redundant, hot-swappable fan arrays down the back. The fans are autonomic: Rotation speeds vary automatically depending on ambient temperature. According to Rackable, cooling represents 8 percent of the CloudRack's overall power consumption compared to 25 percent found in competing blade server systems. "We're consuming up to 800 watts of power per cabinet for cooling. That's remarkable compared to what the competition is doing. A 42U cabinet sold by people like Dell consumes 5,000 to 5,300 watts of power for cooling. North of 25 percent of the entire power consumption goes to cooling fans -- not to mention the noise," said Atashie.
To reiterate Rackable's intriguing claim: The system is capable of running safely in an elevated temperature environment, as high as 104 degrees Fahrenheit, which sets a high bar for other server-hardware vendors. (For a point of comparison, ASHRAE [American Society of Heating, Refrigerating and Air-conditioning Engineers] recently said it was OK to run datacenters at as high as 80.6 degrees Fahrenheit.)