Provyn Prep · System Design competency
Data & storage in the System Design assessment
Data & storage is one of the areas a Provyn System Design credential scores separately, so a recruiter can see it on its own rather than averaged into one number. This guide explains what it covers, how it is tested and what to practice.
What it covers
Data modeling, caching strategies, partitioning and sharding, and picking a storage engine for an access pattern.
Topics in the practice set for this area
- caching
- sharding
- data modeling
- data structures
How it is tested
In the timed assessment, questions in this area use these formats: matching, multiple choice, short answer, system design canvas. Each attempt draws its own set of questions, and this area gets its own sub-score on the credential when the attempt includes enough questions from it. The assessment questions themselves are never published; the practice set below is written separately for study.
What to practice
- Compare cache-aside, write-through and write-behind and when each goes stale.
- Choose a shard key for an example dataset and describe the hot-spot risk.
- Model the same feature in a relational and a key-value store.
Try a practice question
From the free practice set (5 questions in this area). Answers and explanations are in the practice set.
- A CDN primarily improves:
- Caching invalidation strategy 'write-through' means:
- Sharding by user_id with N shards is most fragile when:
Practice before the real thing
Both are free and use practice questions only, never questions from the real assessment.
More System Design study guides
Last reviewed 2026-10-06.