Re: Operate until failure

[David Lesher <wb8foz () nrk com>]

Unnamed Administration sources reported that Sean Donelan said:
> And what if you are not using APCs?

See the menu of systems listed at:

        http://www.exploits.org/nut/

> One issue with highly redudandent data centers is the failure modes are
> "interesting."  You don't want to shutdown due to a single UPS failure, so
> you don't use something simple like PowerChute Plus.  You most likely don't
> want to shutdown based on any automatic signal.  However, you do want a way
> for an operator to gracefully shutdown a lot of equipment quickly when
> the decision is made.
>
> For a server farm, with potentially thousands of individual systems, is
> there any standard piece of software you can install on all of the systems
> to act as a receiver of a signal to begin a graceful shutdown that does
> not depend on a vendor's proprietary interface?  Preferabally one which
> does not involve running a lot of additional wires.

Good point; you'll likely need a box just to talk to UPSi and
control shutdowns. That alas, is adding a single point of failure.

> Again this is only needed if people want a gracefull shutdown.  If
> you can live with a hard shutdown, you wouldn't require this.  If you
> use ctrl-alt-del as a normal management practice, I suspect you don't
> really require a graceful shutdown.

You really don't want to run all the UPS batteries flat. It will
lengthen the recovery time.... (If graceful shutdown is your goal;
when power is restored, you want the UPS to FIRST recharge enough
so it can again gracefully shutdown, when the power turns out to
be back up for just a minute or two....thus you delay restarting
the load.)




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