Good scalable fault-tolerant in-memory database with LINQ support for .NET

Question

Are there are good in-memory transactional databases that support LINQ and SQL Server persistance? I'd like to create a full representation of a large data store in memory and have it commit to a SQL Server Database in a lazy fashion, but still keep some level of fault tolerance by scaling it out horizontally. I don't want to rely on non-relational datagrams like CouchDB.

Answer 1

SQL Server with an ORM tool and possibly a caching solution.

Answer 2

SQLite supports in-memory databases has transaction support and has a Linq provider as well.

As for the SQL Server persistance, I think you would be on your own to code up something for doing lazy transfers to a backing SQL Server database.