nut/docs/powersaving.txt

Desc: NUT Powersaving features and using outlet collection
File: powersaving.txt
Date: 14 June 2003
Auth: Arnaud Quette <arnaud.quette@free.fr>

This document introduces NUT PowerSaving features, and Smart
Outlet Management using Network UPS Tools.

This feature is sponsored by MGE UPS SYSTEMS.

Introduction
------------

This feature, which is supported by various manufacturers,
under various names, allows to manage separately the outlets
of an UPS, or a Power Distrubition Unit (PDU). This allows to
program a limited backup time to non-critical loads in order
to keep the maximum of the battery reserve for critical
equipment. This also allows a remote electrical management of
devices, which is very useful in DataCenters for example. 

On small setup, you can plug printers, hubs, (...) on
PowerSave'd outlets. During a power outage, the UPS will
turn off those after X minutes of back-up time (or when
passing below X % of battery charge) depending on your
UPS model and settings. This will ensure that all
remaining battery power is available for the computer.

On huger setup (with a huger UPS), this is about the
same with the ability to (power and) control servers in
a smart way (need to notify those to shutdown first !).

Manufacturers Powersaving technologies presentation
===================================================

1) MGE UPS SYSTEMS and MGE Office Protection Systems
----------------------------------------------------

This feature is called "PowerShare" and is available
on lots of models, with different behaviours.

Features will vary according to your exact model. 
For example:

- on Pulsar Ellipse Premium 650/800/1200, you can
only set a low battery level which triggers a power
off of the PowerShare outlet(s).
Check http://www.mgeups.com/products/pdt230/smallups/ellipsep/ellipsep1.htm

- on Pulsar Evolution (all models), you can either
do the same as above, or set a timer to shutdown
the outlet when expired. This latter needs to be
used in conjonction with upsmon/upssched to act
upon a power outage, and cancel the timer when
the power is back...

2) Eaton | Powerware ePDU

Depending on the exact model, you can see various measurements
(like current, voltage, power, ...) of the various outlets. You may
also have the hability to start, stop and cycle these.

For more information: http://www.epdu.com

3) Other manufacturers (Belkin, ...)

To be completed...


Integration into the new NUT naming scheme
==========================================

Have a look at new-names.txt, "outlet" section.


Note on outlet collection usage
===============================

1) outlet.{id, desc, ...} represents the
whole outlets (includes all outlet.x.*),
also called Main Outlet.

An interesting fact is that _ALL_ models
have at least that outlet, which is always
considered as the UPS itself. Some values
from the "ups" collection are linked to
the outlet.*, ie:
	- outlet.load is mapped from ups.load
	- outlet.delay.* is mapped from ups.delay.*
		
2) Indexes for other outlets begin by 1. So
the first outlet is "outlet.1.*".


Examples of upsc tree
=====================

1) Here is an MGE Evolution tree with the
main and 2 outlets.

...
outlet.desc: Main Outlet
outlet.id: 0
outlet.switchable: 0
outlet.1.autoswitch.charge.low: 0
outlet.1.delay.shutdown: -1
outlet.1.delay.start: -1
outlet.1.desc: PowerShare Outlet 1
outlet.1.id: 1
outlet.1.switch: 1
outlet.1.switchable: 1
outlet.2.autoswitch.charge.low: 0
outlet.2.delay.shutdown: -1
outlet.2.delay.start: -1
outlet.2.desc: PowerShare Outlet 2
outlet.2.id: 2
outlet.2.switch: 1
outlet.2.switchable: 1
...


2) Here is another MGE Ellipse Premium
tree with the main and 1 PowerSaving
outlets.

...
outlet.desc: Main Outlet
outlet.id: 0
outlet.switchable: 0
outlet.1.autoswitch.charge.low: 0
outlet.1.desc: PowerShare Outlet 1
outlet.1.id: 1
outlet.1.switch: 1
outlet.1.switchable: 1
...