/blobd

Blob storage designed for huge amounts of random reads and small objects with constant latency

Primary LanguageRustOtherNOASSERTION

blobd

Extremely fast and parallel object storage, performing at raw device speeds. Designed for millions of concurrent random partial reads over trillions of objects (tiny or huge) with constant latency.

  • All the good stuff: shared-nothing architecture, io_uring, async Rust for I/O, no page cache, direct I/O.
  • Guaranteed durability: safe to crash at any time, and a success result means the data has been 100% persisted.
  • Create partitions to locally shard within or across block devices or files for extremely high create and delete throughput.
  • Available as embedded library, RPC server, or HTTP RESTful server with CORS, range requests, presigned URLs, and HTTP/2.
  • Asynchronous replication and event streaming.

Design

  • On-device configurable fixed-size hash map with linked list of objects on the heap. The entire device is mapped to memory.
  • Optimised for reads, then creates, then deletes. There is no way to list objects.
  • Create an object, then concurrently write its data in 16 MiB parts, then commit it.
  • Objects are immutable once committed. Versioning is currently not possible. An object replaces all other objects with the same key when it's committed (not created).
  • Only the size is stored with an object. No other metadata is collected, and custom metadata cannot be set.
  • The device must be under 256 TiB. Objects are limited to 1 TiB. The peak optimal amount of objects stored is around 140 trillion.
  • Uncommitted objects may be deleted after 7 days. Space used by objects may not be immediately freed when the object is deleted.

History

This project used to be called Turbostore and was written entirely in C; you can still see the code here.