[c-nsp] Cat6500 power supplies mixing

[Phil Mayers]

On 04/06/10 08:20, Sergey Nikitin wrote:
> Hello,
>
> Does anyone have an experience in mixing power supplies with different
> wattage in WS-C6509? According to this document:
> http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide/pwr_envr.html
> power supplies with different wattage will not work in redundant mode:
> "The system does not allow you to operate a power supply of different
> wattage even if the wattage is higher than the installed supply. The
> inserted supply shuts down."
>
> The question is: with redundancy disabled (with different wattage power
> supplies), if one of the power supplies goes down, will the modules
> powered by this supply go down (even for a small time)? The power of the

I don't think so.

> lower-wattage supply is enough for the whole system.

I've never tried this specific configuration, but I don't think 
"redundancy" means quite what you think it means. IIRC, "redundancy" 
mode just means the box will refuse to power up more linecards than a 
single PSU will drive. There's no difference to how the power is 
supplied to the rails in the box.

If your lower-capacity PSU will support the whole box, you should be 
fine; however beware of the way you balance inputs, since the PSU might 
require both inputs to be powered to deliver its full rating.