Skip to tutorial content
Rate module Not yet rated

Maintenance Windows and Blackout Schedules

4 min read
On this page

In this lesson, you will learn:

  • What a maintenance window is
  • What a blackout schedule is
  • How SNWR uses both
  • How to build them

🔁 Quick look back: Last time: Risk Conditions and Change Success Score. You learned how a risk condition raises risk automatically, and how Change Success Score shows a team’s track record.

1 “You changed it during quarter-end?!”

Last year, someone patched the finance server on the last day of the quarter.

  • The server didn’t come back for four hours.
  • Finance couldn’t close the books on time.
  • The CFO was not happy.

🎯 The problem: Changes at the wrong time hurt the business, even when they go well technically.

👉 The fix: set maintenance windows for when changes are welcome, and blackouts for when they’re not.

2 Two kinds of schedule

Key term: Maintenance window

A time when changes to a CI are planned to happen, like Sunday 02:00 to 06:00.

Key term: Blackout schedule

A time when changes are not allowed, like the last week of each quarter.

SNWR's change windows. Maintenance window: SNWR Sunday maintenance, every Sunday 02:00 to 06:00, for snwr-mail-01, snwr-mail-02 and snwr-vpn-gw-01; changes are welcome here. Blackout: SNWR Quarter-end freeze, the last 5 working days of each quarter; no changes except emergencies.
Figure 1. Welcome here. Not here.

3 How they’re used

  • A CI’s Maintenance schedule field points to its maintenance window.
  • Blackouts apply to everything, or to a group of CIs.
  • Conflict detection checks both, as you’ll see next.

💡 Good to know: Pick windows when few people work. At SNWR, Sunday early morning is quiet in both India and the UK.

⚠️ Heads up: Emergency changes can still happen in a blackout, but Mei must know why.

4 Let’s try it: build the window and the blackout

  1. Go to All › System Scheduler › Schedules › Schedules. Create SNWR Sunday maintenance, type Maintenance, with a weekly entry Sunday 02:00 to 06:00.
  2. Open the CI snwr-mail-01 (or any server CI on your PDI). Set its Maintenance schedule to SNWR Sunday maintenance.
  3. Create SNWR Quarter-end freeze, type Blackout, with an entry for the last five working days of this quarter.
  4. Check both appear in the schedules list with the right type.
  5. You’ll use them to test conflicts in the next lesson.

5 Quick recap

  • A maintenance window says when changes are welcome
  • A blackout says when changes aren’t allowed
  • SNWR: Sunday 02:00–06:00 window; quarter-end freeze
  • A CI’s Maintenance schedule field points to its window
  • Emergencies can still happen in a blackout

6 Check yourself

Think of your answer first. Then tap to check.

1 When is SNWR’s maintenance window? Show answer

Every Sunday, 02:00 to 06:00.

2 What’s the quarter-end freeze? Show answer

A blackout: no changes in the last 5 working days of each quarter, except emergencies.

3 Which field links a CI to its window? Show answer

Maintenance schedule.

4 Can an emergency change happen during a blackout? Show answer

Yes, but Mei must know why.

Nice work! SNWR’s changes now land at safe times. 🎉
Next up: Conflict Detection

Was this lesson helpful?

Have a question or doubt?

Ask here and get help from instructors and fellow learners.

0 / 300

Only logged-in learners can post.