HP BL460c HP BladeSystem c7000 Enclosure technologies,4th edition - Page 27

load.4 They also lower standby power for reduced power consumption when servers are idle. The HP 2400W high efficiency power supplies operate at 200-240V high line only and require BladeSystem Onboard Administrator firmware version 2.40 or later. The high efficiency 2400W power supplies do not interoperate with existing 2250W power supplies. A pair of power distribution units (PDUs) is required for AC line redundancy. PDU options are available in the c-Class infrastructure QuickSpecs: http://h18000.www1.hp.com/products/quickspecs/12517_div/12517_div.html. HP recommends single-phase enclosure models for most situations. At the time of this writing, most typical c-Class customer configurations that HP builds do not exceed 6 kVA for a worst case load. For example, under normal operating conditions, a system configuration of 16 server blades with 2 CPUs each, 4 to 8 GB of RAM, Ethernet, Fibre Channel, and all components at 100% load uses approximately 4 to 4.5 kVA. In customer environments, most systems will probably consume less than 4 kVA because all components will not be at 100% load simultaneously. Actual measurements of real customer applications show usage numbers between 3 and 3.5 kVA. A rack with four three-phase enclosures would require 8 x 30A three-phase power whips and would supply roughly 70 kVA to the rack, of which no more than 18 to 24 kVA would be used. The three-phase c-Class enclosure is generally useful in only a few situations: When there is only one enclosure and there will never be more than one enclosure When the configuration is extreme (for example, 16 server blades with 2 high-power CPUs, 32 GB of RAM, all mezzanine connectors and switch bays filled, running high-performance technical computing loads) When the enclosure is a drop-in replacement for a p-Class solution where three-phase power already exists When the customer plans to maintain the enclosure for a long period of time and to update the internal components with newer ones that could take advantage of full three-phase power capacity Greater power efficiency results from delivering three-phase power to the rack and using single-phase power within the rack. This can be achieved by using the S332 or S348 PDU to run 2 x 60A threephase power to the rack, connected to three or four single-phase enclosures in the rack. If power capping technology is used in this scenario, enclosure power consumption will never exceed 4.3 kVA, meaning it will not exceed the capacity of the PDU, even if an AC line were to fail. NOTE US/Japan three-phase enclosures use a different type of threephase power than International enclosures. For more information, see the ―Power basics for IT professionals‖ technology brief available on the HP website: http://h20000.www2.hp.com/bc/docs/support/SupportManual/ c01234421/c01234421.pdf. Pooled power All the power in the c7000 enclosure is part of a single power pool that any server blade within the enclosure can access. This provides maximum flexibility when configuring the power in the system so that customers can choose the required level of redundancy. Because this power design has no zones, it facilitates both N+N and N+1 power modes, which future-proofs the enclosure for higher power requirements, if needed. Therefore, looking forward at least five years, HP believes there is sufficient power capacity to handle future power-hungry devices. 4 For more information about power supply efficiency, see the 80 PLUS® website: http://www.80plus.org/manu/psu/psu_detail.aspx?id=41&type=1. 27