[nSLUG] linux home or workplace automation and Universal Powerline Bus

D G Teed donald.teed at gmail.com
Mon Sep 22 12:31:30 ADT 2008


On Sat, Sep 20, 2008 at 6:17 PM, George N. White III <gnwiii at gmail.com> wrote:

> I did think about setting up a machine room net just
> for monitoring and control, but the power wires are
> already there and have to be there, while extra
> network cables and jacks will always be a source
> of confusion (figuring out how to configure the 2nd
> port on a new system, making sure the control net
> remains free of data traffic when it would be so easy
> to get around a bottleneck between two systems
> by sending the traffic over the control net, etc.

In a nutshell, I think you are saying you have multiple network
problems, even when the power is up, and you'd like
to automate system shutdowns due to loss of power or
A/C loss.

I think I would opt for the above solution you have here.
It is certainly less than $80,000 to set up a back door
network which will be reliable.  Problems like configuring the
second ethernet device are not that hard to overcome - perhaps
different on oddball OSes, but once it is determined, then
there is the method for the next instance like it.
Running more network cables is a bit of effort but
remember you don't need to do it again for that system.
You will be free of the constraints from Ottawa.  Perhaps bite
off the problem in smaller bits.  Pick 48 systems you really care about
and have secondary ethernet devices, buy a new
48 port switch and use the open source software.  If the
problem was merely the existing switches, then the
problem is left behind.

apcupsd is reliable in my experience.  It does not shutdown
due to remote network apcupsd daemon being unreachable, but it
should make some local complaints if this is the case.
The recent versions will not try to reverse the decision to power down
if the power returns after the shutdown was initiated.  This
was done to ensure the system is running with all intended
services if it is up.

--Donald



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