N+N and N+1 Redundancy

[Mi77]

What is N+N and N+1 Redundancy and what is or are the differences of these 2 power redundancy?

[Michal Kapalka (mikap)]

hi,

check this page, maybe it will help you :

http://en.wikipedia.org/wiki/Uninterruptible_power_supply

mikap

[Michal Kapalka (mikap)]

hi,

this is in Blade specification :

Full power redundancy with N+N hot-plug power supplies and the flexibility of N+1 redundancy

and also some thread about N+N / N+1

[Broken link removed on <4/18/2017> by Mod]

mikap

[Mi77]

Hi Mikap,

I did not get it still, does that mean that If I have 4 Power Supplies, for N+1 I can configure one of the 4 PS to be the standby and the remaining 3 to be Active? For N+N does that mean I can configure 4 PS into 2 Active and 2 Standby or in 6 PS for N+N config I can set 3 Active and 3 Standby?

[THAKUR]

Hi..

Yes..your understanding is correct.
for N+1 - suppose you have 4 PS, 3 will be active and 1 will act as standby(redundancy).

for N+N - suppose you have 4 PS, 2 will be used, and rest 2 will be for standby(redundancy)

[Mi77]

Thanks Thakur, this forum is really great with helpful people's contribution :-)

[Rishi2]

What if there are only 2 PS? Is it:

N+1 - 1 active & 1 standby

N+N - 1 active & 1 standby

Then this means there is no difference among N+1 & N+N redundancy in case of 2 PS? 

Does N+1 meant both the 2 PS to be in active mode (active-active} in this case?

[NiMaec]

Hello Rishi2:

N+1 and N+N are by default terms used in a redundancy context.

When you only have 2 PS, you can't speak about N+N as that isn't redundant. With 2 PS there is only N+N possible.

Rgrds,