Direct Attached Storage (DAS): A Simple and Cost-Effective Storage Solution
Understand Direct Attached Storage (DAS) and its applications. This guide explains how DAS connects storage devices directly to a computer, its advantages (simplicity, cost-effectiveness), and when it's the appropriate choice compared to network-attached storage (NAS) or storage area networks (SANs).
Direct Attached Storage (DAS): A Simple Storage Solution
What is Direct Attached Storage (DAS)?
Direct Attached Storage (DAS) is a storage solution where storage devices (hard drives, SSDs, tape libraries) connect directly to a computer or server without needing a network connection. This provides a simple and straightforward way to increase storage capacity for a single system.
How DAS Works
DAS devices connect directly to a host computer using a Host Bus Adapter (HBA). The HBA facilitates high-speed data transfer between the storage device and the computer. This direct connection is what distinguishes DAS from network-attached storage (NAS) and storage area networks (SANs).
Types of DAS
- Internal DAS: Storage devices installed inside the computer or server.
- External DAS: Storage devices connected externally to the computer or server via cables (using protocols like SCSI or Fibre Channel).
DAS vs. Network Attached Storage (NAS)
| Feature | DAS | NAS |
|---|---|---|
| Connection | Directly attached to a single device | Network-attached |
| Data Access | Block-level access | File-level access |
| Complexity | Simple | More complex |
| Setup | Easy | More involved |
| Cost | Generally lower | Generally higher |
| Capacity | Limited | Higher scalability |
| Data Sharing | Not shared across network | Shared across network |
| Protocols | SCSI, SAS, SATA | CIFS/SMB, NFS |
DAS vs. Storage Area Network (SAN)
| Feature | DAS | SAN |
|---|---|---|
| Connection | Directly attached | Network-attached (specialized network) |
| Data Access | Block-level | Block-level |
| Complexity | Simple | Complex |
| Setup | Easy | More challenging |
| Cost | Lower | Higher |
| Scalability | Limited | High |
| Data Sharing | Not shared across network | Shared across network |
| Protocols | SCSI, SATA | Fibre Channel, iSCSI |
Conclusion
DAS offers a straightforward and cost-effective storage solution, well-suited for smaller systems or situations where network-based storage isn't required. For larger organizations or applications requiring shared storage across a network, NAS or SAN solutions are more appropriate.