Hi everyone,
We bought a 9508 model Nexus switch. It has 4x3KW power supplies on it. Our setup needs about 4KW power budget. I was researching about the power redundancy modes and there is something I could not understand. Cisco says there are three power redundancy mode. Those are:
Combined (nonredundant) | This mode does not provide power redundancy. The available power is the total power capacity of all power supplies. |
insrc-redundant (grid redundancy) | This mode provides grid redundancy when you connect half of the power supplies to one grid and the other half of the power supplies to the second grid. The available power is the amount of power available through a grid. To enable grid redundancy, you must connect the power supplies to the correct power grid slots. For example, on the Cisco Nexus 9508 switch, slots 1, 2, 3, and 4 are in grid A, and slots 5, 6, 7, and 8 are in grid B. To configure and operate in grid redundancy mode, you must connect half of your power supplies to the slots in grid A and the rest of your power supplies to the slots in grid B. For more information on power grid slot assignments for your power supplies, see the Site Preparation and Hardware Installation Guide for your specific Cisco Nexus 9000 Series platform. |
ps-redundant (N+1 redundancy) | This mode provides an extra power supply if an active power supply goes down. One power supply of all the available power supplies is considered an extra power supply, and the total available power is the amount provided by the active power supply units. |
Since our setup only needs for 4KW power and we have 12KW total available, even if I use combined mode, I can see no difference from other modes for redundancy. For example, if two of power supplies disable, there will be still 6KW there and I will have applied redundancy operationally. So why are those modes exist? I think all of them supplies the same redundancy in my scenario.
Kind Regards,
Ahmet Mustafa Mungan
