For open source you can use PostgreSQL or MySQL. I don't know about MySQL, but PostgreSQL databases and table will scale up into the trigabytes; 64 trigs comes to mind. PostgreSQL essentially splits the database in 1 gig increments, so the 2 gig limitation isn't a problem on any OS, since they all can handle at least a 1 gig file. It is my understanding this is the same method used by most commercial databases like MSSQL, Oracle, DB2, Sybase, etc.
Regards,
LelandJ