An comparison of storage area networks and network-attached storage

Storage area networks and network-attached storage provide networked storage solutions. A NAS is a single storage device that operates on data files, while a SAN is a local network of several devices.

The differences between NAS and SAN can be seen when comparing their cabling and how they're connected to the system, as well as how other devices communicate with them. However, the two are sometimes used together to form what's known as a unified SAN.

SAN and NAS technology does not require a specific computer operating system, although many of these devices use Linux under-the-hood.

An illustration of the differences between SAN and NAS.

Overall Findings

  • Local network that uses Fibre Channel to connect several data storage devices.

  • Transitioning from Fibre Channel to the same IP-based approach of NAS.

  • A dedicated hardware device that connects to a local area network, usually through an Ethernet connection.

  • Many NAS devices now offer performance capacities once reserved for SAN.

A NAS unit includes a dedicated hardware device that connects to a local area network, usually through an Ethernet connection. This NAS server authenticates clients and manages file operations in much the same manner as ordinary file servers, through well-established network protocols.

To reduce the costs of standard file servers, NAS devices generally run an embedded operating system on simplified hardware and lack peripherals like a monitor or keyboard and are instead managed through a browser tool.

A SAN commonly uses Fibre Channel interconnects and connects a set of storage devices that share data with one another.

Network Access: NAS Devices for Home Convenience

  • Ideal for large-scale enterprise networks.

  • Not practical for home or casual use.

  • Ideal for home network management.

  • Connect one or more NAS devices to scale up data access in a network.

The administrator of a home or small business network can connect one NAS device to a local area network. The device is a network node, much like computers and other TCP/IP devices, which maintains its IP address and communicates with other networked devices.

Given that the network-attached storage device is attached to the network, the other devices on that network have easy access to it if proper permissions are set up.

Because of their centralized nature, NAS devices offer an easy way for several users to access the same data, which is important in situations where people collaborate on projects or follow the same company standards.

Using a software program provided with the NAS hardware, a network administrator can set up automatic or manual backups and file copies between the NAS and the other connected devices. Therefore, a NAS device is also useful for the opposite reason—to offload local data to the network storage device's larger storage container.

This capability ensures that individual users don't lose data since the NAS can be backed up on a regular schedule regardless of the end user's ability to back up. It also gives other network devices a place to keep large files, especially large files that are shared among network users.

Without a NAS, you need another, often slower, means to send data to other devices on the network, like over email or physically with flash drives. The NAS holds many gigabytes or terabytes of data, and administrators can add additional storage capacity to their network by installing additional NAS devices, although each NAS operates independently.

Scalability and Performance: SAN for Large-Scale Data Storage

  • Meant for industrial or commercial networks with many terabytes of data and high-speed transfers.

  • Requires a vast array of NAS to match the industrial capability of a SAN.

Administrators of large enterprise networks may require many terabytes of centralized file storage or extremely high-speed file transfer operations. While installing an army of many NAS devices is not a practical option, administrators can instead install a SAN containing a high-performance disk array to provide the needed scalability and performance.

Almost no home users have a solid business case for a SAN, although many power users at home make great use of NAS technology.

However, SANs are not always physical. You can create virtual SANs that are defined by a software program. Virtual SANs are easier to manage and offer better scalability since these are hardware independent and controlled entirely by easy-to-change software.


Final Verdict: NAS Is Catching up With SAN

Some SAN products have made the transition from Fibre Channel to the same IP-based approach that NAS devices use. Also, with the rapid improvements in disk storage technology, NAS devices now offer capacities and performance that once were only possible with SAN.

These two industry factors have led to a partial convergence of NAS and SAN approaches to network storage, effectively creating high-speed, high-capacity, and centrally located network devices. 

When SAN and NAS are joined together into one device in this way, it's sometimes referred to as unified SAN. Also, it's often the case that the device is a NAS device that uses the same technology behind SAN.

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