SD-4N · Four Nines · 99.99%

Runbookly Certified System Design Specialist

Proves you can keep systems running at the Four Nines level of the System design lab: you solved the level in the simulator, then built and repaired real systems in a timed practical exam, without being able to test them.

Practice: 4 tasks · 70 %
Theory: 20 questions · 30 %
Duration: 2 h 30 min + 2 pauses of 10 min
To pass: 70 % overall, 60 % in practice
Results: 24 hours later
Valid: 24 months

The exam: practice first, then theory

70 %

Practice in the simulator

4 tasks in the lab you trained in: systems to build from a brief, or to repair. Some come from the level's exercises with other data, most were written for the exam only and are never published.

During the exam you cannot run the simulation: you build or repair, then submit. After the exam our servers replay each system through its day of traffic and failures, and grade it against its objectives.

30 %

Theory

Questions on production situations and on the concepts of the level, drawn for you among the level's exercises and the certification's own bank.

You pass with 70 % overall and at least 60 % in practice: a certified engineer must make systems hold, not only know the answers.

What to master

Every concept below can be asked, and every exercise of the level becomes a scenario of the exam.

The level's exercises

Read the preparation guide →