What is SQL Server 2008 R2's alternative to Oracle 11g RAC?

Greeting Overflowers,

What is SQL Server 2008 R2's alternative to Oracle 11g RAC ? How do they compare ?

I need to utilize cheap computers running the same database for mostly read-only parallel/distributed queries.

Rega开发者_StackOverflow社区rds

mysql sounds like a cheap alternative on cheap hardware. No OS licensing. SQL Server is better than Oracle - or is it the other way around? If you could list more requirements, recommendations might be made.