Storage

Keeping bytes safe and findable at scale: durability engines, erasure coding, replication, and the metadata that locates every object.

Explainers

• Design a Durable Key-Value Store — Start with a hash map behind a socket; end with a crash-survivable storage engine. The write-ahead log — append before apply, fsync, and replay-on-recovery — is the whole story, drawn and computed.
• Design S3-Like Object Storage — From one server writing files on disk to an exabyte store that survives an entire data-centre dying — the metadata/data split, erasure coding, placement across failure domains, and repair as the real durability lever.