Bug or feature?

Great Feature: I see operations and DBA with two separate processes to backup servers and databases. In the new era of snapshots, we can now backup everything. This allows a very quick recovery without the need to build servers, install SQL, and restore databases manually. (I like this very much.)

Feature: SQL Server will (recent update) respond to a FULL VSS snapshot using COPY_ONLY on a read_only database. This prevents the snapshot from failing. (Okay, but why stop there?)

Lost opportunity (i.e., bug): SQL Server does not respond to a FULL VSS snapshot using COPY_ONLY on a writeable database. A COPY_ONLY is a valid backup that does not affect the backup chain. COPY_ONLY is what should always be used by a snapshot until snapshots can be used for point-in-time restores. Perhaps it requires additional coding to safely flush data to disk without updating the diff map?

Lost opportunity: SQL Server does let DBA control the snapshot response. It also might be time to let DBA prevent the transaction log backup to NUL.

The design choice made by Microsoft cost several of us our weekend. There is more work ahead for us to insure operations and DBA collaborate correctly on this. It might not be a bug, but all this would have been unnecessary if the COPY_ONLY design was correct to start with. COPY_ONLY exists just for this sort of thing.