c7000 power management configuration

[Chris Cornish]

We have six PSU installed and power management is configured for N+N. We have lost a power feed and it isn't expected to return for a couple of months. Therefore we now only PSU 1,2 and 3 with power. We cannot now power on blades (existing blades are still running), the blade says unable to power on due to an enclosure power event. According to the OA we have a total of 6750W available and using just over 1400, the allocation is 3154 out of 3154 which is why I suspect we cannot power on the blade. I have been advised to switch to N+1 but the wording the loss of more than one PSU will cause the enclosure to power down puts me off as we already have three failed PSUs. I am considering the not redundant option at the moment but I currently feel whichever option I go with will be the wrong one. Does anyone have any advice on how best to proceed.

[Sivaramakrishna_1]

Hi,

Dont try to change the power option to N+1 as already 3 Power supplies are down.

My suggestion would be why can't you connect the First 3 Power supplies also to the available source insted of keeping them to off for months of time.

[Chris Cornish]

Good point, but we don't have any capacity to connect any more PSUs to the existing PDU. I was on the understanding N+N being the preferred configuration but I now feel this has some serious side effects. Any advice on the impact of using the not redundant option, this seems as it would actually be the most redundant option as it would allow both feed and PSU failures. We monitor our enclosures using SCOM so we would still be notified of any PSU failures.

[Sivaramakrishna_1]

Hi,

There is one option, but it may require some downtime on the exiting setup.

If u have 4 Power connectors, Connect those to Power supplies 1,2,4,5 and change the configuration to N+1 and Remove the Power supplies 3 and 6 from the Enclosure.

With the case i hope the warning will go off and u can use in Power supply redundant mode and u can power on remaining blades.

Again this depends on the Zones(Try to populate the blades one the slots except 7,8, 15,16 so this will become Zone4 Free)

with above consideration hope u can use all the servers till power restores.

[Chris Cornish]

I was able to get one more PSU connected from the working PDU so after redistributing the power I have PSU 1,2,4 and 5 connected and working with N+N. I also had to perform a reset server x for some of the blades that would not power on prior to this.

[Chris Cornish]

and removed PSU 3 and 6