#durability

6 durability interview questions, asked at Databricks, Netflix, Amazon and 1 more company. Last asked Sep 2026.

Durable event log writer shared by thousands of threadsCodingMany threads on one server append small opaque records to a single durable log. Design and partly build the writer: how callers hand off records, how writes are batched and…
Last asked Sep 2026
Design a single-node in-memory cache with a write-ahead logSystem designDesign an in-memory key-value cache that sits inside one web service. Then make it survive restarts with a write-ahead log, and explain how you would shard it and cut lock…
Last asked Sep 2026
Design a file backup systemSystem designDesign a system that backs up files from many machines and restores them on demand. You may assume basic file operations exist; focus on how backups work. Cover full versus…
Last asked Apr 2026
Design a disk-backed key-value store under heavy contentionSystem designDesign a key-value store that keeps its data on disk and serves many concurrent readers and writers, some of them hammering the same keys. Cover the on-disk layout, the write path…
Last asked Mar 2026
Design a cloud database's write path and crash recoverySystem designDesign how writes flow through a managed cloud relational database: from a client's commit to durable storage, how the data is replicated across machines or zones, and how the…
Last asked Jan 2026
Design a crash-resilient file systemSystem designDesign a file system that can recover file contents correctly after a crash at any moment. Cover write ordering, journaling or copy-on-write, what is guaranteed after fsync, the…
Last asked Dec 2025