PowerEdge PSU redundancy options - differences?

Hello Alexander-36725,

 

These may be helpful for you:

 

Full Redundancy vs. Fault Tolerant Redundancy for PowerEdge Server PSUs

https://dell.to/3zaYD91

 

Full Redundancy  configurations  run  at  full  performance  during  normal  operating conditions and after PSU redundancy loss (if a PSU goes down due to input  loss  or  fault).

summary–PowerEdge users looking to adopt FR gain consistent PSU performance during normal and fault operating conditions, but will require a PSU capacity capable of supporting full performance power requirements

 

Fault Tolerant Redundancy  configurations  run  at  full  performance  during  normal  operating conditions, but after PSU redundancy loss, intelligent platform power control loops may dynamically reduce system performance to limit the platform’s power consumption within the capacity of the healthy PSU.

summary–PowerEdge users looking to adopt FTR will have richer platform configuration options within a PSU capacity limit, but must assess the potential impact of performance degradation to their workload

 

 

The iDRAC GUI online help has more information:

 

Redundancy  Policy

 

*Not Redundant—If a PSU fails, the system may shut down

 

*A/B Grid Redundant—power supplies are divided into Grid A and Grid 8.

If a grid or a PSU on one grid fails, but the PSUs on the second grid are

Functional, the system does not shut down. Grid redundancy depends on

the system configuration.

 

*PSU Redundant—If any one of the PSUs fails, the system does not shut

down. PSU redundancy depends on the system configuration

When PSU redundancy is used, the PSUs are not divided into

grids Each PSU is considered as an individual contributor

 

Hot spare is a Power-Supply Unit (PSU) feature that configures

redundant PSUs to turn off depending on the server load.

This allows the remaining PSUs to operate at a higher load and efficiency.

 

Thats exactly one of the articles i found, and like i said it only seems to talk about diff between FR and FTR.

So the question remains: The difference between "redundant" and "fully redundant"?

Hello Alexander-36725,

 

I hope this comparison can help answer your question.

 

PSU Redundancy has 3 possible settings

    * Not Redundant - Every PSU contributes to the server's power. This can allow the server to reach its maximum possible power draw, but the lack of redundancy also means that if one PSU fails, the server can experience an outage.

    * A/B Grid Redundant - The PSUs are divided into grids. In a 4-PSU server, PSUs 1 and 3 are in Grid A, while PSUs 2 and 4 are in Grid B. In this scenario, if a PSU in Grid A fails, then the server will seamlessly failover to Grid B.

   * PSU Redundant - Similar to A/B Grid Redundant, except that the PSUs are not grouped into grids. Instead, each PSU is an individual contributor to the server's power, allowing for more redundancy. This option is not available in every server.

 

 

Full Redundancy  configurations 

Run  at  full  performance  during  normal  operating conditions and after PSU redundancy loss (if a PSU goes down due to input  loss  or  fault).  FR  is  optimized  for  consistent  performance,  thus the  minimum  PSU  capacity  allowed will  ensure that  the  platform configurations full performance power requirements can be supported.

In summary–PowerEdge users looking to adopt FR gain consistent PSU performance during normal and fault operating conditions, but will require a PSU capacity capable of supporting full performance power requirements.