In the DAS concept, the hard disks are directly assigned to a computer system and are connected to it. Hence the name Direct Attached Storage (DAS). The hard disks are often housed in a case with the motherboard and other plug-in cards.
The data is transferred via SCSI, SATA or other interfaces at block level. In terms of expanding storage resources, the DAS concept is relatively costly and also inflexible due to the limited number of hard disk controllers and hard disks or solid-state drives. In addition, the servers through which all the data flows are a bottleneck. Since the hard disks and the processors are relatively close to each other, the data throughput is relatively high.