UPS expectations

[Corey Edwards]

On 06/26/2012 12:00 PM, Kyle Waters wrote:
> Due to nearby construction we have had a couple of power outages 
> recently and I've been asked to evaluate our batter backup system(we are 
> not able to put generators in place currently). I have a few questions 
> for other regarding there batter back up systems.
> 
> What is a reasonable expectation for a rack mountable UPS to continue to 
> supply power during a power outage?
> 
> How much equipment do you generally put on one 
> UPS(servers,switches,routers)?

These two questions are very closely related. The more equipment on a
single UPS, the less runtime. The more batteries, the longer it runs but
the bigger it gets and the more rack space it eats. It's a tradeoff
between $$ and time, so decide how much you can afford.

Just for comparison, I have some places that have generator backup and
the UPSes only need to last 10-20 minutes. Other sites are on the top of
mountains and their UPSes last 8-10 hours.

> Any software you have found that works well with CentOS to shut down the 
> servers at the appropriate time?

Not specifically, but we like the APC management cards. They're easy to
tie into whatever monitoring solution you have (*cough* Zenoss *cough*).
In fact, just now I'm going through a power outage at a remote site and
I know that the AC is out, the battery is at 36% and it has 60 minutes
runtime remaining.

> How frequently should UPS be tested? How should they be tested?

More often than they actually get tested.

> How frequently do you replace batteries/UPS' due to failure?

Not frequently enough.

Corey