Power-Saving for £0

1. Power-Saving for £0 Lisa Nelson University of Liverpool

2. The Problem • Computers often left on all the time, regardless of whether they are in use • Changing people’s behaviour is difficult • Need an automatic power-saving mechanism

3. The Goal • Reduce power consumption • When PCs are idle • Without risking losing data • At no cost

4. Use Built-In Windows Capabilities? • Hibernate? • Excellent power reduction • Can have issues in network environments • Standby? • Good power reduction • Same potential issues with network environments • Power down hard disks? • In practice, did nothing • Stores settings for the current user! • No management by policy!

5. Use Third-Party Utilities? • Cost • Client utilities • E.g. LocalCooling • All limited to underlying Windows capabilities = same problems • Centrally-managed utilities • Can only schedule = less aggressive

6. Conclusions • Shut down • But only when nobody is logged on • Not very aggressive, but safe • Excellent for walk-up computers • Can be done with batch files and freeware utilities for £0

7. How It Works • Setup batch file: • Create a scheduled task to run power-saving batch file (as the System user) after N minutes idle • Copy power-saving batch file somewhere local • Also copy two freeware utilities • Power-saving batch file: • Determine whether anybody is logged on • If not, shut down

8. Possible Problems • Some people may legitimately need to opt out • Running grid applications with nobody logged on • Acting as a server • So supply a discretionary opt-out mechanism • Psshutdown flagged as dangerous • NOT a problem: erroneously shutting down when somebody is logged on

9. Our Results • No problems • Statistics: • Shutdowns per day: ~4,500 • Total computers participating: ~3,500 • Average daily downtime: 33,350 hours = >1,000,000 hours per month! • Average daily MW (assuming 100 W): 3.3 MW • Average daily kg CO2 (0.43 kg/kW): 1,400 kg

10. Want to Try It? E-mail me: lisa.nelson@liverpool.ac.uk Or go to http://pcwww.liv.ac.uk/powerdown

11. Limitations • No reporting • Not very flexible • Inconvenient to modify after rollout • Not very effective for staff-style working patterns

12. The Big Limitation What if you want to do more?

13. PowerMan: Overview • Single executable • Copy into place and run POWERMAN INSTALL • Runs as a service • Controlled by group policy • Easy to modify • Built-in reporting

14. PowerMan: Features • Control monitor, disk, computer idle timeouts • Actions: log off, stand by, hibernate, power off • Specify different actions and timeouts for: • When a user is logged on vs. no user • Running on AC vs. DC • Exceptions (files or processes, Server service) • Scheduled wake and shutdown

15. PowerMan: Reporting • Built-in reporting • Easily see overviews or detail down to individual computers • Easy to identify your culprits

16. How We Use PowerMan • Walk-up: • Force logoff after 3 hrs idle • Hibernate after 10 mins when nobody is logged on • Staff: • Can choose what to do when idle: • When a user is logged on; e.g. stand by after 30 minutes • When nobody is logged on; e.g. hibernate after 10 minutes

17. Results

18. Where We Are Now • All our power-saving is now being done by PowerMan • Walk-up: <1 hr idle/day • Staff: • Still in progress – ~2000 computers yet to choose settings • But have cut idle time by 25%; anticipate eventually 75% • Previously 1,000,000 hrs/month; anticipate eventually 2,000,000

19. Want to Try It? E-mail: info@datasynergy.co.uk Or go to http://www.datasynergy.co.uk