[epaulson]

This sentence is doing a lot of work: "Hypothetical S2 does a bit more to simplify the layers above – it makes leadership above the log convenient with leases and fenced writes."

It'd be awesome to have a bit more transactional help from S3. You could go a long way with 'only update this object if the ETags on these other objects are still the same'. I know AWS doesn't want to turn S3 into a full database but some updates you just can't do without having a whole 2nd service running alongside to keep track of the states of your updates.

[shikhar]

Agreed, both Google Cloud Storage and Azure Blob Storage support preconditions. Azure even has leases. S3 is for better or worse the common denominator for systems layering on top of object storage.