1. Retail SLA Proposed Changes RMS/TDTWG September 2008 Trey Felton IT Account Manager

2. 2 Apr – Jun 2008

3. 3 Sample Data For complete data set see: Retail SLA_Transaction Stats.xls

4. 4 Weekend Transaction Volume during Outage Window Timeframes (1-year average vs 3-month average) Current Release Window Proposed Release Window

5. 5 Summary SLA Proposed Changes –Add 6 hours to Week 1 Currently 12 hours –Move 36-hr release window to Week 4 Currently in Week 2—busiest week –Add a 12-hour outage window in Week 5s (Mar/May/Aug/Nov) Not in current SLA November will not be used for a release or week 5 outage Rationale –5-week Months become general outline for major releases (Mar/May/Aug/Dec) Extra weekend gives additional outage window opportunity –Remaining months will be reserved for minor releases

6. 6 Additional Considerations For 2009 –Move November Week 4 Outage to December Week 2 To accommodate for Thanksgiving Holiday –Move May Release up 1 week (to Week 3) To accommodate for Memorial Day –Analyze Quarterly Release concept For 2010 –Reduce monthly minor release windows if possible

7. 7 Proposed Release Calendar (2009)

8. 8 TDTWG Recommendations Limit Maintenance Window request to 15 hrs –Yes Reduce Release Outage to 30 hrs –Cannot Support Marketrak available 8am – Noon on Saturday –Yes Have 1 weekend a month with zero outages –With our current systems, ERCOT cannot support –Targeted for 2010

9. 9 Proposed Maintenance/Release Windows for 2009 MAINTENANCE  1 st and 2 nd Sunday– 6:00am until 9:00pm Sunday (15 hours)  Option 2: Sunday– 9:00am until 12:00am Monday (15 hours)  3 rd and 5 th Sunday—8:00am until 8:00pm (12 hrs)  Option 2: Sunday—10:00am until 10:00pm (12 hrs)  RELEASE: 4 th weekend– 12:00pm Saturday until 12:00am Monday (36 hours)  Option 2: 10:00am Saturday until 10:00pm Sunday (36 hours)

10. 10 Maintenance Outages (since Jan 1, 2008) ERCOT Proposed SLA (18 hours) Current SLA (12 hours) Average = 9.8 hrs TDTWG Proposed (15 hours)

11. 11 Current / Proposed SLA (36 hours) TDTWG Proposed (30 hours) Releases (2007-2008) Average = 26.4 hrs 20% took more than 36 hrs 33% took more than 30 hrs

12. 12 Marketrak

13. 13 Impacts to Data Extracts SLA Maintenance Windows: –1st, 3rd, and 4th Sunday of each month – 8:00am until 8:00pm (12 hours) New Maintenance Windows –1st and 2nd Sunday—6:00am until 9:00pm (15 hours) –3rd and 5th Sunday—8:00am until 8:00pm (12 hours) Release Window: –2nd weekend of each month – 12:00pm Saturday until 12:00am Monday (36 hours) New Release Window: –4th weekend*– 12:00pm Saturday until 12:00am Monday (36 hours) Availability Breakdown: Gross minutes per year = 525,600 (unchanged) Reserved maintenance outage minutes per year = 25,920 (new SLA 32,940) Reserved release outage minutes per year = 25,920 (new SLA 23,760) 525,600 – 51,840 = 473,760 net availability minutes per year (New SLA) 525,600 – 56,700 = 468,900 net availability minutes per year 99% availability = 4,737 unplanned outage minutes per year, or 78.9 hours (if all available maintenance and release windows are used) 99% availability = 4,689 unplanned outage minutes per year, or 78.15 hours (if all available maintenance and release windows are used) (New SLA)

14. 14 Backup Slides

15. 15 Release Outage (apportioned time) Start TimeSat 12:00pm Shut down apps and clear queues1.5 hrs New Code Migration4 - 6 hrs Bring Systems Back Up / Tech Verification1 hr Production Verification4 hrs Rollback Contingency1 - 4 hrs Minimum Time Needed 11.5 – 16.5 hrs Variations June Release: Planned 11 hrs, Actual 24.8 hrs (Prod verification failure; rollback) July Release: Planned 9 hrs, Actual 9 hrs Average Release has been 24 hrs (since Jan 1, 2008)

16. 16 2008 Net Service Availability 15 July, 2008ERCOT Confidential

17. 17 Releases (2008) Current / Proposed SLA (36 hours) Average = 24 hrs TDTWG Proposed (30 hours)