[ale] centralized vs separate UPS?

[Jim Kinney]

The way I would approach this is from the standpoint of, "What machine
_can_not_ fail ungracefully." If a machine can fail gracefully, can it be
offline? If the answer is no to both, I would be totally paranoid and
order a UPS for the individual machine _and_ a generator for the entire
room. The other factor is, "how long of a power outage are you willing to
work through?" If it's measured in minutes, skip the generator. If the
server room needs to function while the building burns down around it, get
the generator. Also consider the physical proximity problem of "where do I
put the power bricks?" A 420W UPS is about the 1/2 the size of a mini
tower. There are rack mount UPS for rack mount systems. Put the rack mount
bricks on the bottom. They are too heavy for any where else when they are
sized enough to run the whole rack. Also remember, you are buying time in
two phases, phase 1 is run time after power failure, phase two is
lifetime of the battery in service. 

James Kinney M.S.Physics		jkinney at teller.physics.emory.edu
Educational Technology Specialist	404-727-4734
Department of Physics Emory University	http://teller.physics.emory.edu

On Wed, 9 Jun 1999, Pete Hardie wrote:

> Eric Webb wrote:
> > 
> > And now for something completely different...
> > 
> > I'd like to open a small discussion on your theories for computer room UPS
> > systems.  I'd like to see how you would configure a computer room backup
> > system if you were designing it.  Consider such a computer room to contain
> > nearly a dozen machines, some at 110V and some at 220V.  This computer room
> > is not at a corporate HQ, but a regional site which also happens to be the
> > company's national call center and largest distribution facility.
> > 
> > I guess the biggest thing that I am curious about is would you configure a
> > centralized, redundant mass backup system or would you configure each
> > server with its own UPS?
> 
> I'd say it depends on the purpose of backup.
> 
> If the room is set up for a bunch of systems that need 24/7 availability,
> I'd probably go for a centralized power backup, since most of the machines
> would need to stay alive.
> 
> If outages are acceptable, but the power backup is for preservation of
> delicate systems (DB need to be shutdown cleanly, etc), I'd look into
> individual backups with good power management systems (PowerChute is a
> brand name that comes to mind [not an endorsement, just an ad meme])
> 
> OTOH, looking at the costs for individual UPS vs one big one (both
> installation and maintaining them), and it might be cheaper to go with
> a central system.
> 
> -- 
> Pete Hardie                   |   Goalie, DVSG Dart Team
> Scientific Atlanta            |
> Digital Video Services Group  |
>