DAS, NAS, Or SAN – Choosing The Right Storage Architecture

Running any modern business requires processing large quantities of data. You need a convenient way to store and access it. Your storage architecture should also provide you with timely data backups and a reliable recovery system if you want to reduce financial risks. There have been a few innovations in the field of data storage architecture, and entrepreneurs can choose the preferable storage method based on its availability, complexity, price, and maintenance costs.

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Three main options exist on the market right now: DAS, NAS, and SAN.

  • DAS stands for Direct Attached Storage,
  • NAS is Network Attached Storage,
  • and SAN means Storage Area Network.

Most companies opt for network solutions like SAN & NAS while others choose direct-attached storage (DAS). Let’s compare the differences in these storage methods and find out which solution fits your company better.

Direct Attached Storage

DAS is usually considered to be the least expensive, basic approach to creating a data storage system. With DAS, a server or a workstation is connected directly to the storage device. It’s a 1 to 1 relationship. Common varieties of this storage architecture include external hard disks, tape libraries, server HDDs. Even a USB stick attached to your computer can be considered an example of DAS.

DAS can use different means of connection, including USB cables. Enterprise-level DAS solutions rely on such protocols as SAS, SCSI, FCP, SATA, and eSATA. Large DAS units can contain dozens of drives. However, they are all attached to a single machine with no network in-between. Based on the location of the storage device, all DAS solutions are classified as internal or external.

If you need a low-cost solution with a high-speed connection, choose an internal DAS solution. It is connected to the server using a physical bus (serial or parallel). The disadvantages of this approach include a limited number of storage devices, complicated maintenance, and a shorter connection distance (limited by the bus itself).

External DAS architecture requires the server to be connected to a remote storage device using FCP or SCSI. Multiple servers can communicate with a remote storage array. The advantages of this approach include centralized management and maintenance. The connection speed is slightly reduced compared to internal DAS.

Should You Choose DAS?

DAS is perfect for smaller businesses and teams. It’s fast, inexpensive, and easy to maintain. However, it’s almost impossible to scale. DAS is not the architecture to use when you need to share data across large distances or collaborate with a lot of users.

Network Attached Storage

NAS is the choice popular both with smaller companies and enterprise-level businesses. This data storage method requires creating a centralized storage system that can be accessed by multiple devices through a network.

A typical NAS device has multiple SSD or HDD enclosures, where the disks are combined using a RAID array. It usually has a reasonable level of built-in redundancy which prevents data loss in case one or more drives in the device become unresponsive. The drives can be swapped as well. NAS architecture relies on protocols like NFS, CIFS, or SMB. Storage devices come in all shapes and sizes. Larger NAS solutions are often found in data centers.

NAS is often seen as the next step from DAS. Companies looking to consolidate their direct-attached storage devices combine them (or migrate data) into a NAS system. NAS is also more reliable in the case of power outages compared to DAS.

If you need to build an email system for your employees from different offices, support accounting databases, operate a CRM or analytics software with multiple data channels, NAS is a good choice.

Should You Choose NAS?

If you run a medium-sized company or a startup looking to scale fast but don’t want to spend too much money, NAS is an adequate solution. It’s scalable, reliable, provides centralized control and maintenance options. It can be used in connection with a cloud server. You can expand it fast to accommodate your increasing data needs or mass user influx. On the downside, NAS is usually not enough for enterprises and data centers that need to transfer extremely large amounts of data fast.

Storage Area Network

SAN is the option usually reserved for enterprise-level businesses and large data centers. In essence, it combines the convenience, reliability, and security of NAS with the data retrieval speed of DAS solutions. Every SAN represents a high-speed network with block-level data transfer support. SANs are fairly complicated and consist of multiple devices including storage, switches, hosts, and connectors. They can use several protocols, including iSCSI, FCP, or FCoE, and be present in different locations physically. Supporting a SAN solution requires a dedicated IT team.

SAN uses multiple data paths and virtualization. Because of that the end user’s device “perceives” the data storage as locally attached. Applications that run on SANs have better availability and performance. Storage resources are used more efficiently. Data is protected from external threats and losses. SAN solutions are provided by major IT vendors worldwide.

Should You Choose SAN?

SAN is a more expensive and complicated solution that can be excessive for most small and medium-sized companies. But if you need to run complex applications that work with extremely sensitive data, then SAN is your best option. A well-maintained SAN solution is a lifesaver for a large corporation or a data center. But if you are a smaller business or startup, then DAS or NAS are the better options.


Choosing a data storage solution boils down to the available budget and your company’s needs. Smaller businesses should opt for less sophisticated solutions that can be easily maintained. Corporations and data centers that work with sensitive data should consider going the SAN route.

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