NAS vs SAN: Differences and use cases

These two storage architectures, both NAS and SAN, are complementary because they compete and respond to different needs and use cases in the organization. Many larger organizations own both.

NAS and SAN don't tell the whole story when comparing these two common storage architectures. NAS and SAN are complementary because they compete and respond to different needs and use cases in the organization. Many larger businesses can own both.

However, IT budgets for businesses are not limitless and organizations need to optimize their hosting costs to match their priority requirements. This article will help you clarify that by identifying NAS and SAN, highlighting their differences, and offering use cases that are suitable for both architectures.

Definition of NAS and SAN

Network Attached Storage (NAS)
A NAS is a file-level data storage device that is attached to a TCP / IP network, usually Ethernet. It usually uses NFS or CIFS protocols, although there are also other protocols such as HTTP.

The NAS is present on the operating system as a shared folder. Employees access files from the NAS the same way they work with any other file on the network. NAS depends on LAN, if LAN does not work, so does NAS.

NASs aren't usually as fast as block-based SANs, but high-speed LANs can overcome most performance and latency issues.

Storage Area Network (SAN)
SAN is a high-performance network dedicated to unified block-level storage. The network connects storage devices, switches and storage servers. High-end enterprise SANs can also include SAN directors for higher performance and efficient capacity utilization.

The server connects to the SAN fabric using a master bus adapter (HBA). The server identifies the SAN as locally-attached storage, so many servers can share a storage group. The SAN is not dependent on LANs and reduces the pressure on the local network by reducing the load of data directly from attached servers.

NAS versus SAN: 7 major differences
1) Fabric. NAS uses TCP / IP network, the most popular being Ethernet. Conventional SANs often run on high speed fiber channel (FC) networks, although many SANs are using IP-based fabric because of the cost and complexity of FC. High performance is still a SAN requirement and flash-based fabric protocols are helping to bridge the gap between slower FC and IP speeds.

2) Data processing. Two different data processing storage architectures: NAS processes file-based data and SAN processes block data. The story is not quite as simple as that of course: NAS can operate with global namespaces and SAN has access to dedicated SAN file systems. A global namespace aggregates multiple NAS file systems to present a unified view. The SAN file system allows servers to share files. In SAN architecture, each server maintains a dedicated, non-shared LUN. The SAN file system allows servers to securely share data by providing file-level access to servers on the same LUN.

3) Protocol. The NAS connects directly to the Ethernet network through a cable into the Ethernet switch. NAS can use several protocols to connect to servers including NFS, SMB / CIFS and HTTP. On the SAN side, servers communicate with SAN drive devices using the SCSI protocol. The network is formed by using SAS / SATA fabric types or mapping layers to other protocols, such as Fiber Channel Protocol (FCP) mapping SCSI over Fiber Channel or iSCSI mapping SCSI over TCP / IP.

4) Performance. SANs are higher performers for high-speed traffic environments such as high transaction databases and e-commerce websites. NASs typically have lower throughput and higher latency due to the slower file system layer, but high-speed networks can compensate for performance losses in NAS.

5) Scalability. Entry-level and entry-level NAS devices are not highly scalable, but high-end NAS systems scale to petabytes using scaling clusters or nodes. In contrast, scalability is a major driver of SAN buying. Its network architecture allows administrators to extend performance and capacity in extended or extended configurations.

6) Price. Although a high-end NAS will cost more than the entry-level SAN, it is generally less expensive to buy and maintain. NAS devices are considered devices and have fewer hardware and software management components than the storage network. Administrative costs are also included in the equation. SAN is more complex to manage with FC SAN on top of the complexity. A good rule of thumb is to calculate 10 to 20 times the purchase cost as an annual maintenance calculation.

7) Easy to manage. In a one-to-one comparison, the NAS won the competition for easy management. The device easily plugs into LAN and provides a simple management interface. SAN requires more administration time than NAS devices. Implementation often requires making physical changes to the data center and ongoing management often requires specialized administrators. The exception to the SAN-is-hard argument is that many NAS devices do not share the common management console.

The use cases for NAS and SAN
NAS and SAN serve different needs and use cases. Understand what you need and where you need it.

NAS: When you need to merge, focus and share.
· File storage and sharing. This is the main use case of NAS in remote offices, SMBs and businesses. A single NAS device allows IT to unify multiple file servers for simplicity, ease of management and space and power savings.

· Active hosting. Long term storage is best stored on less expensive storage such as tape or cloud-based cold-storage. NAS is a good choice for searchable and accessible data storage, and high-capacity NAS can replace large tape libraries for storage.

· Big data. Businesses have several options for big data: NAS scaling, distributed JBOD nodes, all-flash and object storage. The NAS is great for handling large files, ETLs (extracting, converting, downloading), intelligent data services such as automated stratification and analytics. NAS is also a good choice for unstructured big data like video surveillance and playback, and post-production storage.

· Virtualization. Not everyone is sold when using NAS for virtualized networks, but the use case is growing and both VMware and Hyper-V support their data warehouse on the NAS. This is a popular choice for small or new virtualized environments when the enterprise does not yet own the SAN.

· Virtual desktop interface (VDI) Mid-range and high-end NAS systems provide native data management features that support VDI such as fast desktop cloning and data copying.

SAN: When you need speeding, scaling and protection.
· Database and e-commerce website. Serving a shared file or NAS will make the database smaller, but a high-speed transaction environment requires SAN SAN high I / O processing speed and very low latency. This makes the SAN suitable for high-traffic business databases and e-commerce websites.

· Quick backup. The server operating system considers the SAN as an attached storage, allowing quick backups to the SAN. Backup traffic does not go through the LAN because the server is backing up directly to the SAN. This helps to back up faster without increasing the load on the Ethernet network.

· Virtualization. NAS supports virtualization environments, but SANs are better suited for large-scale and / or high-performance deployments. Storage area networks quickly transfer multiple I / O flows between virtual machines and virtualization servers and high scalability allows for dynamic processing.

· Edit video. Video editing applications need very low latency and very high data transfer rates. SAN provides this high performance because it connects directly to the video editing desktop client, delivered with an additional server layer. The video editing environment requires a distributed third-party SAN file system and controls load balancing on each node.

SAN and NAS combined
Unified SAN / NAS (or multiple protocols) combine files and storage blocks into a single storage system. These unified systems support up to four protocols. The storage controller allocates physical storage to handle NAS or SAN.

They are popular for mid-range businesses who need both SAN and NAS, but lack dedicated datacenter and admin space for separate systems. Converged SAN / NAS is a small part of the market compared to different deployments but shows steady growth.