These numbers are totally insane. I've never seen a Rust project with a build cache this large.

Do you have 10 different versions of Tokio included in your project or something?

The project I'm currently working on is quite large, and it's locally cross-compiled to 5 different arch/OS combinations, plus a debug build for the local machine. The build dir is 9.1 GB. I've seen it grow to somewhere around 20 GB, but only after a significant number of dependencies were updated, or the compiler version changed.

A clean debug build of Bevy (a game engine, one of the largest Rust projects around) produces a target dir of around 13 GB. By the way, rebuilding Bevy on my machine takes about 1 minute.

Now, these numbers are still much bigger than I would have preferred, but 329 GB? Get out of here.