SAN, NAS or DAS: Which is the right storage for you?


In recent years, Storage has become a critical component of an organization’s IT Infrastructure. As organizations accumulate tons of business-relevant data, storing and accessing it efficiently becomes critical to the success of the business.


Storage has evolved over the last 3 decades to become sophisticated and complex at the same time, so properly scoping and sizing storage required for the organization involves a lot of due diligence. Much of the dilemma lies around which of the three paradigms of storage should the organization adopt: SAN, NAS or DAS? It’s then good to know what each of these stands for, what their unique advantages are, and when is one more suitable than the other?


Types of Storage-Platform Architecture

  • SAN or Storage Area Networking: SAN, one of the earliest and most popular storage architecture, is noted for its high performance and provides enterprises with a highly scalable architecture to connect servers with a shared pool of storage blocks. The communication between them happens over SCSI-based protocols, such as iSCSI, Fibre Channel (FC) and Fibre Channel over Ethernet (FCoE).
  • DAS or Direct Attached Storage: As the name implies, here the storage is directly attached to the device such as a desktop or laptop unlike SAN where the storage lies on a network. Accordingly, the storage is managed by a single host. Here, data is stored in disks in the host. If more storage is required, they are present in external disk enclosures that communicate directly with storage controllers in the host.
  • NAS or Network Attached Storage: As the name implies, storage or data resides in a centralized location or servers, and is then accessed by one or more networks of users that require this data. One can look at NAS as a kind of private cloud in the organization. This makes it faster, more cost-effective and offers better control for organizations that must serve their customers 24x7 over the Internet. 


Comparative Analysis

SAN is most popular with mid-sized and large enterprises, so it’s useful to compare it with other architectures to decide which is most suited for your organization.

  • Highlights of SAN: SAN’s popularity comes from the fact that on all the key parameters such as scale, capability, performance, availability, resilience and efficiency, it scores high. Unlike the past when SAN typically used rotary-access storage-devices, contemporary SAN uses solid state devices which offer superior performance than such mechanical disk drives. SAN also creates a centralized storage mechanism which makes it easy to provision the storage, analyze the storage performance and make scalability configurations.
  • SAN vs. DAS: While SAN provides several advantages, it’s still a little more expensive than other architectures and slightly complex to manage. In contrast, DAS is less expensive, so servers can be fitted with very large disk drives that hold more storage space. However, since only host is involved, much of the storage is under-utilized. As the number of servers go up, more the underutilized space.
  • SAN vs. NAS: Although NAS systems are similar to SANs, they are only suitable when large amounts of unstructured data resides in the organization.

Choosing between the three architectures requires extensive research on short and long-term data requirements. Engage a consultant, or a professional storage vendor who can also advise you on the same.