When you configure a SQL Server that contains only a few gigabytes of data and does not sustain heavy read or write activity, you are not as concerned with disk I/O and balancing SQL Server I/O activity across hard disk drives for maximum performance. If you build larger SQL Server databases, however, that contain hundreds of gigabytes of data and/or will sustain heavy read and/or write activity, you must configure SQL Server to maximize disk I/O performance by load-balancing across multiple hard disk drives.