Apache BookKeeper

• provides high durability and availability for storing logs (write-ahead logs, transaction logs).
• offers a scalable, fault-tolerant, and low-latency storage solution.
• ensures consistent, ordered, and replicated logs.

bookkeeper separates storage and serving roles:

• bookies: individual storage nodes (similar to datanodes in hadoop) responsible for storing log fragments.
• metadata storage: tracks bookie locations and log segment metadata (zookeeper is commonly used).
• clients: write and read entries to/from bookkeeper (e.g.,apache pulsar).

• distributed messaging systems: providing durable and replicated storage for message streams.
• write-ahead logging: ensuring data consistency and recovery for databases and other systems.
• ledger storage: offering a reliable and performant foundation for distributed ledgers.

• high throughput and low latency: designed for high-performance logging operations.
• scalability: easily scales horizontally by adding more bookie nodes.
• durability and availability: replicated storage ensures data durability and availability.