Not enough power for Gen8 with N+N redundancy

[chuckk281]

Danny had a customer question:

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We did a power sizing calculation for one of largest customers for c7000 with 16 BL460c Gen8 blade servers.

-          Each BL460c with 2 x E5-2680, 16 x 16GB RAM, 2 x 300 GB HDDs, 1 x 530 FL and 1 x Qlogic adapter, at 70% utilization.

-          c7000 with 2 x Flex-10 and 2 x VC-FC and 6 x Plat 2400W PS.

-          Data center works at 230V

When configured with N+N redundancy, the power advisor result in power error stating that more power is required. When configured with N+1 redundancy the total watt is 5,301W and total circuit size power is 7,889W.

My guess is that the N+N configuration fails because of Circuit Sizing power result.

N+1 is not optional for him as it can't sustain failure of two PS.

My questions is:

What is circuit sizing?

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Info from Jonathan:

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The Circuit Sizing power number is based on an application that stresses the system to “Max Operational Load”.     Products are tested to get this information and then the data is applied to Power Advisor (and Blade Power Sizer).    The way the c7000 system works is that the Onboard Administrator deducts the “Blade Max Power” number for each blade based on each blades actual configuration.   If there is not enough power budget available to support all of the blades at max power for given configurations then some of the blades may not be allowed to power on.    This is done to ensure the power supplies don’t get overloaded.  

Circuit Sizing number is used to describe max power conditions for the given configuration.   This represents applications that heavily stress the system.   This number is what is used to determine how many power supplies are needed to run the system.

Utilization Power is used described what you would expect to see for normal operational power consumption with given percent utilization setting.

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Other comments or questions?