[AusNOG] Bottom of rack UPS

[John Edwards]

On 16/12/2010, at 4:25 PM, Skeeve Stevens wrote:

> Ok, on this. What do people think of doing your own bottom of rack ups in datacentres which supposedly have good protection with UPS and Gensets, but given industry experience, aren't always 100% reliable?
> 
> I'm talking only something that gives a short period of time to deal with cutover delays as exampled here.
> 
> The ups can always be powered by dual feeds with a transfer switch. Thoughts?

In addition to the points others have raised, in most environments power is now at a premium, which means you may only have small capacity breakers to enforce your electrical allocation.

If the power does go out for an extended period of time, the UPS that runs fine day-to-day may just pop a breaker when it attempts to recharge and bear your startup load at the same time.

This gives you a race condition that is not easily resolved at a time when remote hands are probably at their busiest!

For the home electricians, this is also the number two reason why you shouldn't hack a standard power plug onto the cable that comes with a 3KVA or bigger UPS...

John