Compaq ProLiant BL e-Class System Overview and Planning

Compaq ProLiant BL e-Class System Overview and Planning 31
Appendix B: Input Power Budget De-rating
All power requirements for ProLiant BL e-Class server blade enclosures that are discussed in this
document are based on the input power of the enclosure. Compaq recommends using the
maximum rated power supply input of 1000 W when planning power distribution. De-rate the
input power for any of the following reasons:
To minimize the number of PDUs required for each rack
To match the rack current requirements with the existing circuit breaker capacity
To match the rack cooling requirements with the existing facility cooling capability
Note: In this document, de-rating the input power budget means not using the maximum rated
input power values for the power supply. Compaq strongly recommends that you verify that the
de-rated power budget will satisfy all the installation requirements including future upgrade
plans.
IMPORTANT: De-rating may cause your configuration to lose redundancy. Verify each PDU’s
output circuit breaker can support the de-rated load, including load re-distribution caused by a
power-supply failure, PDU failure, or AC source failure.
IMPORTANT: Violation of any restriction could result in a “domino effect” that may disrupt
power to the enclosure, multiple enclosures, or the entire rack.
Calculate the de-rated value by using the supplied worksheet at the end of this appendix.
To de-rate the input power, start with the base configuration from the table in Appendix A. Add
the peak power of the components included in the desired system configuration to calculate the
de-rated power budget.
Assume the desired enclosure configuration is as follows:
1 x ProLiant BL e-Class Server Blade Enclosure; plus
1 x RJ-45 Patch Panel; plus
10 x ProLiant BL10e Server Blades (each with 512-MB memory)