SD-1N · One Nine · 90%
Runbookly Certified System Design Operator
Proves you can keep systems running at the One Nine 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
- 2 tasks · 70 %
- Theory
- 15 questions · 30 %
- Duration
- 1 h + 1 pause 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
2 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.
- Client-server model
- Relational databases
- Latency numbers to know
- Vertical scaling
- Queueing and utilisation
- Cloud cost optimisation
- Single point of failure
- Horizontal scaling
- Load balancing
- Health checks
- Content delivery network
- Object storage
- Storing files outside the database
- Caching
- Cache-aside
- Time to live
- Eviction policies
- Capacity planning
- Failover
- Availability and the nines
- RPO and RTO
- Synchronous and asynchronous replication
- Backups and restore drills