Direct Attached Storage (DAS)

What Does Direct Attached Storage (DAS) Mean?

Direct Attached Storage (DAS) is a dedicated digital storage device attached directly to a server or PC via a cable. Advanced Technology Attachment (ATA), Serial Advanced Technology Attachment (SATA), eSATA, Small Computer System Interface (SCSI), Serial Attached SCSI (SAS), and Fibre Channel are the main protocols used for DAS connections.

The DAS principle is fundamentally straightforward. DAS systems have become more prevalent due to increasing requirements for efficient IT storage solutions. The difference between DAS and Network Attached Storage (NAS) is that a DAS device connects directly to a server without a network connection.

DAS creates data islands, because data cannot be shared with other servers.

Techopedia Explains Direct Attached Storage (DAS)

A typical DAS device may be an internal or external hard disk drive. Depending on data criticality, disk drives may be protected with different levels of Redundant Array of Independent (or Inexpensive) Disks (RAID). Modern DAS systems include integrated disk array controllers with advanced functionalities.

DAS advantages include:

• High availability.
• High access rate due to Storage Area Network (SAN) absence.
• Elimination of network setup complications.
• Storage capacity expansion.
• Data security and fault tolerance.

DAS drawbacks include:

• Data not accessible by diverse user groups.
• Allows only one user at a time.
• High administrative costs.