You can use the filesystem but then you have to manage data migration/sync by "hand" which is kind of a bitch for distributed systems.
Honestly storing large blobs with meta-data telling you about the blobs is extremely common. I'm yet to hear of how you're meant to do it correctly.
Generally it seems to be that if you have lots of unique large files then use filesystem. But if you have files which are likely to have duplicates then use a database. So a file storage locker may use (1) but a service like iTunes Match would use (2). And IIRC Apple in fact does store at least uploaded music files in Cassandra.
The OP doesn't appear to have hear of SQL Server FileStream or FileTables, which handle this abstraction for you: http://msdn.microsoft.com/en-us/library/ff929144.aspx