What is the importance of customized data spaces in SQL Server and what are the quantitative measures that can be used to efficiently design this?
A tablespace creates a layer of abstraction between physical and logical data

By using tablespaces, an administrator can control the disk layout of an installation. A common use of tablespaces is to optimize performance. For example, a heavily used index can be placed on a fast disk. On the other hand, a database table which contains archived data that is rarely accessed could be stored on a less expensive but slower disk.