UPS expectations

[Victor Villa]

On 6/26/2012 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.
Hi Kyle,

Before answering your qq with a big "it depends", i thought i'd point
you to this http://www.apc.com/tools/ups_selector/

because honestly, it does depend on the size of the UPS and what you
have running :)

> What is a reasonable expectation for a rack mountable UPS to continue to 
> supply power during a power outage?
I can keep all servers and switches running for 45 minutes, then i'm
done.  I've been very clear with my bosses that we can extended this,
but at $.  So they fully understand 45 minutes is what they get with the
money they've invested.  They also understand that there will be a need
for battery replacement.  I'm using several APC UPS 3000XL.

> How much equipment do you generally put on one 
> UPS(servers,switches,routers)?
on this part, i guessed though i'd love to hear what other say.  As i
say, i have several UPSs (all the 3000xl), so i have 1 power supply
plugged into 1 3000xl and the other power supply from the same server
plugged into the other (2 3000xl per rack, 3 racks).  This way if i have
a failure on one UPS, the server (hopefully) won't go down.  The 3000xl
has software that tells you how the batteries are and how big of a
strain you're putting on things.  It also provides the time estimate at
current load, that it can support.

>
> Any software you have found that works well with CentOS to shut down the 
> servers at the appropriate time?
no experience, would love to hear solutions from others
>
> How frequently should UPS be tested? How should they be tested?
i check them about monthly, the software tells mes what my status is

> How frequently do you replace batteries/UPS' due to failure?
dpends on utilization i guess


mj/v