Apache DistributedLog (DL) is a high-throughput, low-latency replicated log service, offering durability, replication and strong consistency as essentials for building reliable real-time applications.
Apache DistributedLog project graduated from Incubator at July 2017. It is now a sub-project of Apache BookKeeper.
The core components of Apache DistributedLog has been merged as part of Apache BookKeeper. The development of Apache DistributedLog has been moved under BookKeeper. See BP-26: Move distributedlog library as part of bookkeeper for more details.
DL is able to provide milliseconds latency on durable writes with a large number of concurrent logs, and handle high volume reads and writes per second from thousands of clients.
Messages are persisted on disk and replicated to store multiple copies to prevent data loss. They are guaranteed to be consistent among writers and readers in terms of strict ordering.
DL provides an efficient service layer that is optimized for running in a multi- tenant datacenter environment such as Mesos or Yarn. The service layer is able to support large scale writes (fan-in) and reads (fan-out).
DL supports various workloads from latency-sensitive online transaction processing (OLTP) applications (e.g. WAL for distributed database and in-memory replicated state machines), real-time stream ingestion and computing, to analytical processing.
To support a large number of logs for multi-tenants, DL is designed for I/O isolation in real-world workloads.
DL has a modern layered architecture design, which separates the stateless service tier from the stateful storage tier. To support large scale writes (fan- in) and reads (fan-out), DL allows scaling storage independent of scaling CPU and memory.
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Apache DistributedLog is an open source project of The Apache Software Foundation (ASF). The Apache DistributedLog project originated from Twitter.