Comment by jschorr

(Co-founder of Quay here)

Scalability and garbage collection are actually two of the main areas of focus Quay has had since its inception. As you mentioned, most modern Docker registries such as Quay and Harbor will automatically redirect to blob storage for downloading of layers to help with scale; Quay actually goes one step further and (for blobs recently pulled) will skip the database entirely if the information has been cached. Further, being itself a horizontally scalable containerized app, Quay can easily be scaled out to handle thousands of requests per second (which is a very rough estimate of the scale of Quay.io)

On the garbage collection side, Quay has had fully asynchronous background collection of unreferenced image data since one of its early versions. That, plus the ability to label tags with future expiration, means you can (reasonably) control the growth problem around images. Going forward, there are plans to add additional capabilities around image retention to help mitigate further.

In reference to your note: We are always looking for contributors to Project Quay, and we are starting a bug bash with t-shirts as prizes for those who contribute! [1]

[1] https://github.com/quay/quay#quay-bug-bash

Edit: I saw the edit below and realized the bug bash is listed as ending tomorrow; we're extending it another month as we speak!