DAS is ideal for local data sharing in businesses with a single non-enterprise server or few servers that share information across short distances. Typical applications for small companies include file serving and email. DAS is also used in larger organizations alongside NAS and SAN storage appliances.
A DAS system connects directly to a computer with a host bus adapter (HBA). Typically, the system contains one or more hard disk drives (HDD). No network interface is utilized. This differentiates DAS from Network Attached Storage (NAS). Since DAS is directly connected to a computer, other computers must access the DAS computer in order to utilize the DAS storage appliance. Some DAS systems provide concurrent access ports for sharing between computers. Drive protocols for DAS systems include ATA, Fibre Channel, SAS, SATA, and SCSI.
A DAS system is easily managed through the local computer operating system. Benefits include modest startup costs, streamlined security management, and less contention for resources. DAS offers a performance advantage over a typical SAN by insuring dedicated service to a single application. Disadvantages, in contrast to NAS and SAN storage, include the inability to share data or unused resources with other servers, lack of controller redundancy, cooling redundancy, and storage fault tolerance patterns (RAID). DAS expansion costs are linear while SAN costs per Gb actually go down as the system size grows. The larger DAS expansion expense is due to the necessary addition of redundant hardware which is part of each standalone appliance. Build or fine-tune your DAS system with ESA's configurator.