What Is Direct-attached Storage (DAS) And How Does It Work?

Direct-attached storage pros and cons

DAS can provide users with better performance than networked storage because the server does not have to traverse a network to read and write data, which is why many organizations use DAS for applications that require high performance. DAS is also less costly and less complex than network-based storage systems, making it easier to implement and maintain.

Additional advantages of DAS include:

• Simplified installation and configuration. Installing DAS is as simple as inserting a storage drive into an available server slot with configuration handled by the server's operating system (OS).
• Cost-effective. Compared to other storage systems, the cost of installing a DAS is nominal. No extra software is needed in addition to the hardware, simplifying configuration changes.
• Enhanced performance. DAS drives generally have low latency compared to networked storage; use of SSDs for DAS can greatly improve performance.
• Security. As DAS is directly connected to the server, risks of security breaches to applications and data are reduced as networking technology is not used.

DAS is not without challenges, however. It has limited scalability and lacks the type of centralized management and backup capabilities available to other storage platforms. Administrative tools such as data replication, available in most SANs and NAS devices, might not be available with DAS. In addition, data cannot be easily shared and DAS doesn't facilitate failover should the server crash. Because of these challenges, conventional forms of DAS might not be suited for many enterprise workloads.

However, advancements in virtualization technologies have breathed new life into DAS, a trend that's been especially apparent in the many hyperconverged infrastructure (HCI) systems available from many hardware and software vendors. An HCI system is made up of multiple server and DAS storage nodes, with the storage consolidated into logical resource pools, providing a more flexible storage solution than conventional DAS.