Gufo Blob Backends

Gufo Blob provides several built-in backends, available in both synchronous and asynchronous modes. All synchronous backends are thread-safe, and asynchronous backends are safe for concurrent async access.

Built-in backends

Backends out of the box:

Backend	Storage layer
memory	In-process memory
file	Local filesystem
sqlite	SQLite database

Data durability

Backends may provide different levels of data durability (persistence across failures). Ordered from weakest to strongest guarantees:

1. Process lifetime - data available in process lifetime.
2. Process crash safety — data survives process restart (in-memory persistence beyond runtime is not guaranteed otherwise)
3. Host crash safety — data survives operating system or host restart
4. Distributed durability (replication) — data is replicated across multiple storage nodes and survives node failure

Data sharing

Backends may also differ in the scope of data visibility and sharing. Ordered from narrowest to widest:

1. Process-local — data is visible only within a single process.
2. Host-shared — data is accessible across multiple processes on the same machine.
3. Network-distributed — data is accessible across multiple hosts over a network.

Backend comparison

Backend	Data durability	Data sharing
memory	Process lifetime	Process-local
file	Host crash safety	Host-shared
sqlite	Host-crash safety 1	Host-shared

Further reading

See appropriate backend documentation for implementation details.

• memory
• file
• sqlite

---

1. Distributed file systems can increase durability. ↩