Date Added: Jan 2010
The primary mode of data storage for computer servers has been direct-attached storage (DAS). In this mode, a computer issues commands to manage blocks of data on internal disk drives. This mode presents constraints to growth as the amount of servers and storage space increases. DAS is not very scalable and is a single point of access. Externalizing storage into a Storage Area Network (SAN) creates a manageable and scalable pool of storage devices. As Steve Duplessie of the Enterprise Storage Group describes it, "Storage virtualization is a paper that avoids incompatibilities and vendor idiosyncrasies, creating a global pool of heterogeneous devices that can be managed as a single entity."