RP8400 cell boards to BPU's

[Alexander Dallas]

I have 4 cell boards in our RP8400 and 5 BPU's for a "N+1" redundent config and all 4 power connections are connected. The weird part is that I am getting messages in syslog that the BPU's are not redundent and wants that 6th BPU in.
also in looking at the manual (http://www.docs.hp.com/en/A6093-96022/ch05s01.html)it states that if you have 2 cell boards you need 4 BPU's for a n+1. my math may be week but last I checked 2+1=3 not 4.
HELP me clean my syslog.
alex dallas

[Torsten.]

This is the rule: for n+1 redundancy with 4 cells you need 6 BPS'.

[Sandy Chen · Accepted solution]

Hi Alex,

You will need 6 BPS, I attached a part of rp84xx documentation about the BPU

Regards,
Sandy

[Alexander Dallas]

that is what I figured but I was tripping on the n+1 where I thought
n = "number of cell boards"
so 4+1=?6?

[Torsten.]

"n+1 redundancy" **always** means one more than needed - 1 can fail and you have still enough to keep it working.
This not only applies to this part ;-)

[Alexander Dallas]

closing thread

[timber]

A simple rule about rp84xx cell and BPS :
for N+1 redundent : BPS num= X+2(x=cell num)
for N(not redundent):BPS num=X+1(x=cell num)