[CentOS] Power Fail Protection Update II

Fri Aug 18 21:23:46 UTC 2017
Chris Olson <chris_e_olson at yahoo.com>

Many thanks once again to those that responded to my original posting
(and my follow up message) with information about Network UPS Tools,
other Linux-based tools like rtcwake, and commercial UPS products.
We have quite a bit more evaluation and testing work to do before
a power fail protection method is selected.  I hope the discussion
is as beneficial to others as it is to my organization.

Along the way, one of our users pointed out that some of our CentOS 6
desktop/deskside machines actually throttle back power consumption in
different ways than others.  Instead of the yellow/amber LED display
in the center of the power button, they flash green and then go solid
green after the power button is pushed and the system wakes up.  We
have also noted that none of our CentOS 6 systems restart on their
own when power is restored. This is the case whether power is lost
during normal operation or when the systems are in a standby state
when line power is lost.

These two conditions or states (yellow/amber vs flashing green) have
us wondering exactly what standby mode these systems are in and what
settings may have been selected to send them to their standby state. 

Is there some sort of standard that applies to the standby states and
are there BIOS settings or configuration files that control the what,
how, and when standby is directed? 

Thanks to all and best regards.