Measuring Progress
A typical PowerMAN deployment is divided into three distinct phases:
- An initial period of passive monitoring. This allows a baseline usage profile to be established
- Deployment of an active power policy. This is designed to reduce energy from the established baseline. Often the specific settings used are chosen based upon both the results of the monitoring phase and existing knowledge about the usage pattern and user requirements
- A post deployment monitoring phase. In this phase the power policy is monitored and areas for possible further improvement may be identified
The most effective PowerMAN deployments use the initial passive monitoring
phase to fully understand the existing usage profile. This passive process
is transparent to users and allows you to collect information that can then
be used to better the specific strategy you use to reduce PC energy waste.
After you have implemented an energy reduction initiative it can be very
useful to refer back to the data previously logged to measure progress and
identify areas for possible further improvement.
Best Practices
Each organisation has specific operating requirements that will require tailored power management settings. Often the perceived drawbacks of using active power management can be dispelled by both a careful deployment and by keeping the users informed. The following tips may help maximise savings:
- PowerMAN works best if it is initially used to monitor an existing configuration. We recommend that you do not apply any active power management until a typical usage profile has been established. Ideally this profile should be established over several weeks. It can be tempting to enable active management early. This isn’t recommended as it will be impossible to determine how effective your deployment has been until you have established a base line figure.
- Dynamic (idle based) policies will achieve larger energy savings than a static, time based, configuration. This is because an idle timeout based configuration allows each computer to function independently and adapt to a changing usage pattern.
- Schedule based settings (for instance shutdown at 7pm) can be used to complement dynamic (idle based) policies. This can be especially useful if the usage pattern is known or when applications are found that inhibit idle based policies from fully working.
- An energy conservation policy works best if it is understood by the users. There are some simple steps you can take such as putting up notices and labelling the power button on each PC that should reduce user frustration and support calls. We have found that most users support active power management if they understand why it is being done.
- The monitor and hard disk settings may be used to reduce energy consumption without risking user data. These should generally always be enabled.
- Similarly, the CPU performance settings can be used to reduce energy consumption with minimal impact on users. Typically these should be set to ‘Adaptive’ when a user is present and ‘Degrade’ when no user is present.
- Screen savers consume energy. Consider turning the monitor off rather than enabling a screen saver.
- Most modern programs fully support sleep or hibernate. These may be used to save energy whilst preserving the user session and any open documents. Sleep and hibernate are most appropriate when the PC is used by the same long-term user.
- When the computer is regularly used by many users (for instance in a hot-desk environment or public access area) sleep or hibernate are rarely appropriate policies for when the user is logged on. This is because both lock the workstation for subsequent users. Instead consider using a logout policy to prevent the system being hogged by an absent user. Typically it can be quite simple to determine a suitable timeout after which the user is assumed to have ‘abandoned’ the computer.
- The power settings appropriate when a user is logged on may be very different from those appropriate when no user is logged on. PowerMAN allows separate user and No User policies to be easily defined. Ideally a power policy should be configured in both situations (even if the user policy doesn’t implement an idle action it can still save significant energy by turning the monitor off or logging the user out after the specified period).
- Power off does not need to be the default action – hibernate or sleep can be used as idle actions when no user is logged on to allow the next user to rapidly logon and become active.
- Similarly, PowerMAN can resume the PC from one sleep state to transition to another. This can be effectively used to use a light sleep (S1-S3) during the daytime when the system is idle but transition to power-off or hibernate (S4) at night time.