Nexus 7010 Power

[Garry Cross]

I need some help to understand the output of show environment power on a Nexus 7010 with 2 x 6K AC power supplies.

The objective being what is going to happen when I plug 2 N7K-M224XP-23L into slot 7 & 8.

Based on the power calculator and the redundancy mode I should have 69.56% of the available power.

Calculator says this module will reserve 795 W per module.

The question, does the system decide to power up a module based on the reserved or the actual consumption?

According to the allocated below, I believe we will fall short and one module will not power up.

That would make the power calculator incorrect in its conclusion.

Power Usage Summary:
--------------------
Power Supply redundancy mode (configured)  PS-Redundant
Power Supply redundancy mode (operational) PS-Redundant

Total Power Capacity (based on configured mode)   6000 W
Total Power of all Inputs (cumulative)           12000 W
Total Power Output (actual draw)                  2266 W
Total Power Allocated (budget)                    4760 W
Total Power Available for additional modules      1240 W

[balaji.bandi]

ps-redundant

This mode reserves the power of one supply in case any power supply fails. The power from the supply that can provide highest power is reserved. The available power is the sum of the remaining power supply units.

here is more explanation  with scenarios :

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/hw/nexus7000/installation/guide/n7k_hig_book/n7k_managing_sys_hw.html

[Garry Cross]

Thank you for your reply. I did not find in the referenced document specifically the answer to my question.

"Is the 7K, going to refuse to power up a module based on the budget or the actual draw?"

If it is the budget, then using the power calculator is only useful in determining how hard the power supply will be driven and not whether all the modules will power up in the given mode for the given configuration.

Based on above the two new modules will budget 795 each and only one module will be allowed to power up unless I change the mode to combined.

Thank you.

[Reza Sharifi]

Hi,

795 W is maxed but typical for that module is 720 W. See table-9 in the link below:

https://www.cisco.com/c/en/us/products/collateral/switches/nexus-7000-series-switches/Data_Sheet_C78-437759.html

So, usually, the power calculator calculates about 30% more than what is actually needed. 

if that is the case, your total wattage for both modules will be around 1008 W.  

720-216=504 per module for a total of 1008 for both.

216 is 30% of 720.

So, you may be able to get away with what you have left (1240 W) without changing anything.

For testing, you can also try inserting one of the modules and calculate based on that.

HTH