Explore the use of Valkey (Redis-compatible KV store) with ccache remote storage

[esteve]

Checklist

• I've read the contribution guidelines.
• I've searched other issues and no duplicate issues were found.
• I've agreed with the maintainers that I can plan this task.

Description

Valkey is a fork of Redis that is developed by the Linux Foundation, with developers from Google, Amazon, and many others.

ccache has support for storing the cache in a Redis-compatible server via https://github.com/ccache/ccache/wiki/Redis-storage

The goal of this task is to explore the feasibility of using Valkey as a remote storage for ccache to improve build times.

Purpose

GitHub has a storage limit for caching, our self-hosted runners are not affected, but most of the CI builds happen in public runners, hence we keep hitting that limit.

Possible approaches

The approach we're exploring here is setting up Valkey on one of our machines and let both the public and the self-hosted runners use it for storing ccache objects.

Definition of done

Results of running Valkey as a remote storage for ccache will be provided at the end of the evaluation.