EntityFramework can also support any underlying database and EF6 has providers for sql server, mysql, postgre, oracle, sqlite and many others. EF7 will even support nosql options like MongoDB.
What exactly is the issue with disk space for a published running app? The GAC (global assembly cache) in Windows was originally designed just for this: to share references and avoid having multiple copies of the same binaries. All this led to was a complicated situation with maintenance and reference nightmares. Disk space is exceedingly cheap and a strange to worry about when picking a tech stack.
They currently have working providers for SQL server, SQLite, SQL Server Compact, and PostgreSQL
When I was talking about disk space I was referring to linux operating system where there is no GAC.
Central places don't work very well and again, file space is very cheap. Most binaries compress down very small so there really shouldn't be a disk space issue. And you can always remove dependencies if necessary.
It's just not something that has ever been a problem in over a decade of building and publishing .NET apps.
I heard that EF 7 which is compatible with ASP NET 5 doesn't support MYSQL database.
Also the disk space when asp net 5 app is published is realy high.
Imagine you have 20 application, it with ~70Mb each one on disk you'll end up with +1GB of packages that you depend on.
I think something like Go, scala or Node JS is better.