HP ProLiant BL660c HP BladeSystem c-Class architecture - Page 25

Availability technologies The BladeSystem c-Class incorporates layers of availability to enable the 24/7 infrastructure needed in data centers. Using redundant configurations eliminates single points of failure, and the c-Class architecture reduces the risk of component failures and the time required for changes. Redundant configurations The BladeSystem c-Class minimizes the chances of a failure by providing redundant power supplies, fans, and interconnect modules. For example, customers have the option of using power supplies in an N+N redundant configuration or an N+1 configuration. The interconnect modules can be placed side-by-side for redundancy, as shown in Figure 6 on page 10. And the c7000 enclosure is capable of supporting either one or two Onboard Administrator modules in an active-standby configuration. Redundant Onboard Administrator functionality is also planned for the c3000 enclosure. The c-Class architecture provides redundant paths through the use of multiple facility power feeds into the enclosures, blade-to-interconnect bay connectivity, and blade-to-enclosure manager connectivity. Because all c-Class components are hot-pluggable, administrators can quickly re-establish a redundant configuration in the event of a failure. Reliable components HP took every opportunity in the c-Class architecture to design for reliability, especially for critical components that can be considered single points of failure. Some customers might consider the NonStop signal midplane for the BladeSystem c-Class enclosure to be a single point of failure, since it is not replicated. However, HP mitigated this risk and made the PCB extremely reliable: • Designed the NonStop signal midplane to provide redundant paths between the server blades and interconnect bays • Eliminated all active components from the PCB that would affect functionality, thereby removing potential sources of failure • Removed power from the NonStop signal midplane to reduce board thickness, reduce thermal stresses, and reduce the risk of any power bus overloads affecting the data signals • Minimized the connector count to reduce mechanical alignment issues • Used mechanically robust midplane connectors that also support at least 10 Gigabit per second (Gbps) high-speed signals with minimum crosstalk The result is a NonStop signal midplane that has a calculated MTBF in the hundreds of years. Some c7000 customers may choose to have a single Onboard Administrator module rather than two for redundancy. In this case, the Onboard Administrator can be a single point of failure. In the unlikely event of an Onboard Administrator failure, server blades and interconnect modules will all continue to operate normally. The module can be removed and replaced without affecting operations of the server blades and interconnect modules. Operating temperatures of components can play a significant role in reliability. As the operating temperature increases beyond specified maximum values, thermal stresses increase, which results in shortened life spans. The PARSEC architecture of the BladeSystem c-Class enclosures minimizes the operating temperature of components by delivering fresh, cool air to all critical components. The airflow is tightly ducted to make every cubic centimeter of airflow count and to ensure the most thermal work from the least amount of air. The server blades are designed with ample room for intake air and heat sinks (both on the processor and memory modules). Rather than use the traditional heat sink design for the processors, HP designed a copper-finned heat sink that provides more heat transfer in a smaller package than traditional heat sinks used in 1U rack-optimized servers. 25