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What is the difference between Direct Attached Storage (DAS) and Storage Area Network (SAN)?

Created on 2025-06-23 14:13:06
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Direct Attached Storage (DAS) and Storage Area Network (SAN) are two distinct storage architectures with different designs, use cases, and performance characteristics.

1. Direct Attached Storage (DAS):
DAS is a storage system directly connected to a single server or a small group of servers via interfaces like SATA, SAS, or NVMe. It is not shared over a network, making it simple and cost-effective for local storage needs.

  • Example: A company attaches multiple hard drives to a dedicated database server for high-speed access. Since the storage is not shared, it avoids network latency but lacks scalability for multiple servers.

2. Storage Area Network (SAN):
SAN is a dedicated high-speed network that provides block-level access to shared storage devices across multiple servers. It uses protocols like Fibre Channel (FC) or iSCSI to connect servers to storage arrays, enabling centralized management and high availability.

  • Example: A data center uses a SAN to allow multiple virtualized servers to access the same pool of storage. This setup supports dynamic allocation, failover, and high-performance workloads like virtualization or databases.

For cloud-based storage solutions requiring scalability and high performance, Tencent Cloud offers Block Storage, which can be attached to cloud servers similarly to DAS, and CBS (Cloud Block Storage) with high availability features akin to SAN.