HardDesign: Distributed Key-Value Store (Redis/DynamoDB)

What is the purpose of a Write-Ahead Log (WAL) in a KV store?

— Tests your understanding of this concept.

Answer Options

ATo log read operations
BTo ensure durability: if node crashes, WAL allows recovery of in-memory data that wasn't yet flushed to disk
CTo distribute writes across nodes
DTo improve write performance

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This question is from the Design: Distributed Key-Value Store (Redis/DynamoDB) topic (System Design Cases).

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