Why Redis’s Master‑Slave Terminology Sparks Debate and What Changes Are Planned

Background

Redis uses a master‑slave replication model, a term inherited from MySQL. After the Redis 5.0 RC5 changelog was published, many developers requested a change of terminology because the words “master” and “slave” are considered inappropriate by some.

Project lead antirez noted that similar requests have been made before and that a recent anonymous Twitter poll showed more than half of respondents supporting a change. However, he argued that renaming would be costly and would introduce several compatibility problems:

Existing pull requests could not be applied without modification.

Commands such as INFO and ROLE currently return replies containing the word “slave”.

The source code contains roughly 1,500 occurrences of the term “slave”.

Private projects that merge Redis code would encounter numerous breakages.

Short‑Term Changes

To address community concerns while preserving backward compatibility, the following interim steps were proposed:

Rename the architectural description from “master‑slave” to “master‑replica”.

Introduce an alias REPLICAOF for the existing SLAVEOF command, allowing both names to be used.

Continue returning the word “slave” in the responses of INFO and ROLE commands, acknowledging that this remains a breaking change for the future.

Long‑Term Changes

Long‑term plans involve more extensive refactoring of the code base:

Develop a replacement for the INFO command that omits “slave” terminology.

Perform widespread internal replacements of the term; many existing pull requests would become inapplicable without substantial modifications.

Further redesigns of replication‑related APIs are anticipated, though concrete details remain open.

Reference links:

http://antirez.com/news/122

https://github.com/antirez/redis/issues/5335