02-28-2020 10:39 AM
ooking for a Power distribution Unit PDU to support a Cisco 9508 that has 8 power supplies,
I attached the hardware reference guide. The wattage used is dependent on the supervisor and line cards in the switch. Initially we have 2 Supervisor B+ (N9K-SUP-B+) modules at 80W each and 2 36-port 100-Gigabit Ethernet QSFP28 line card (N9K-X9736C-FX) at 720W each. That’s 1600W. We anticipate fully
populating the switch with the 100-Gig line cards. So that’s 8 X 720W, plus the SUP-B+ cards = 5920W. Given that, we only need 2 3000W Power supplies. However, this is an always ON application, so I want it to be with n+2 redundancy on generator and non-generator. That’s why I have 8 Power supply per switch.
So the power supply total from one power feed from 2 switches would be 24000W. I’m not sure how that works. If 8 power supplies come on at the same time, do they all try to pull 3000W of power? Do we account for that, or do we account for the fully populated max of 5920W?
03-19-2020 08:05 AM
The power supplies should only ever draw the load required by the hardware. For instance an PC with a 1000 watt PSU will not be constantly drawing 1000 watt if it's only loaded with 250 watt (peak) of hardware [e.g. a Motherboard + CPU say 100 + 150 watt each]. The power supplies will share the load of all the attached equipment at 1/8th. Here are the outputs from my lab switch.
As you can see here, by default it's splitting the load over both Power supplies.
Leaf-7# show en encryption environment Leaf-7# show environment power Power Supply: Voltage: 12 Volts Power Actual Actual Total Supply Model Output Input Capacity Status (Watts ) (Watts ) (Watts ) ------- ---------- --------------- ------ ---------- -------------------- 1 N9K-PAC-3000W-B 731 W 749 W 3000 W Ok 2 N9K-PAC-3000W-B 654 W 696 W 3000 W Ok 3 N9K-PAC-3000W-B 0 W 0 W 0 W Shutdown 4 ------------ 0 W 0 W 0 W Absent Actual Power Module Model Draw Allocated Status (Watts ) (Watts ) ------- ------------------- ----------- ----------- -------------- 1 N9K-X9564PX 228.00 W 399.60 W Powered-Up 2 N9K-X9636PQ 183.00 W 399.60 W Powered-Up 3 N9K-X9536PQ 239.00 W 399.60 W Powered-Up 4 N9K-X9464PX 94.00 W 240.00 W Powered-Up Xb21 N9K-C9504-FM 72.00 W 130.80 W Powered-Up Xb22 N9K-C9504-FM 75.00 W 130.80 W Powered-Up Xb23 N9K-C9504-FM 77.00 W 130.80 W Powered-Up Xb24 N9K-C9504-FM 82.00 W 130.80 W Powered-Up Xb25 N9K-C9504-FM 76.00 W 130.80 W Powered-Up Xb26 N9K-C9504-FM 83.00 W 130.80 W Powered-Up 27 N9K-SUP-B 78.00 W 90.00 W Powered-Up 28 N9K-SUP-B 74.00 W 90.00 W Powered-Up 29 N9K-SC-A 14.00 W 25.20 W Powered-Up 30 N9K-SC-A 14.00 W 25.20 W Powered-Up fan1 N9K-C9504-FAN 31.00 W 129.00 W Powered-Up fan2 N9K-C9504-FAN 30.00 W 129.00 W Powered-Up fan3 N9K-C9504-FAN 31.00 W 129.00 W Powered-Up N/A - Per module power not available Power Usage Summary: -------------------- Power Supply redundancy mode (configured) PS-Redundant Power Supply redundancy mode (operational) PS-Redundant Total Power Capacity (based on configured mode) 3000.00 W Total Grid-A (first half of PS slots) Power Capacity 6000.00 W Total Grid-B (second half of PS slots) Power Capacity 0.00 W Total Power of all Inputs (cumulative) 6000.00 W Total Power Output (actual draw) 1386.00 W Total Power Input (actual draw) 1446.00 W Total Power Allocated (budget) 2843.00 W Total Power Available for additional modules 157.00 W
HTH
Regards,
Jason.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide