Don't want to start a 'my database is...' rant, but have you given Postgres a whirl with said data? It tends to be fairly robust for very large datasets, and i

Don't want to start a 'my database is...' rant, but have you given Postgres a whirl with said data? It tends to be fairly robust for very large datasets, and its performance tends to be excellent under these conditions. Migration from MySQL is straightforward; I use both DBs in separate environments.