Skip to main content

Network-Attached Storage (NAS)


Network-attached storage (NAS) is dedicated file storage that enables multiple users and heterogeneous client devices to retrieve data from centralized disk capacity. Users on a local area network (LAN) access the shared storage via a standard Ethernet connection. NAS devices typically do not have a keyboard or display and are configured and managed with a browser-based utility. Each NAS resides on the LAN as an independent network node, defined by its own unique Internet Protocol (IP) address.
What most characterizes NAS is ease of access, high capacity and fairly low cost. NAS devices provide infrastructure to consolidate storage in one place and to support tasks, such as archiving and backup, and a cloud tier.
NAS and storage area networks (SANs) are the two main types of networked storage. NAS handles unstructured data, such as audio, video, websites, text files and Microsoft Office documents. SANs are designed primarily for block storage inside databases, also known as structured data.
What network-attached storage is used for
NAS enables users to collaborate and share data more effectively, particularly work teams that are remotely located or in different time zones. A NAS connects to a wireless router, making it easy for distributed work environments to access files and folders from any device connected to the network. Organizations commonly deploy a NAS environment as the foundation for a personal or private cloud.
There are NAS products designed for use in large enterprises, as well as those for home offices or small businesses. Devices usually contain at least two drive bays, although single-bay systems are available for noncritical data. Enterprise NAS gear is designed with more high-end data features to aid storage management and usually comes with at least four drive bays.
Prior to NAS, enterprises had to configure and manage hundreds or even thousands of discrete file servers. To expand storage capacity, NAS appliances are outfitted with more or larger disks -- known as scale-up NAS -- or clustered together for scale-out storage.
In addition, most NAS vendors partner with cloud storage providers to give customers the flexibility of redundant backup.
While collaboration is a virtue of NAS, it can also be problematic. Network-attached storage relies on hard disk drives (HDDs) to serve data. Input/output (I/O) contention can occur when too many users overwhelm the system with requests at the same time. Newer NAS systems use faster flash storage, either as a tier alongside HDDs or in all-flash configurations.
NAS vs. DAS
Direct-attached storage (DAS) refers to a dedicated server or storage device that is not connected to a network. A computer's internal hard drive is the simplest example of DAS. To access files on direct-attached storage, the end user must have access to the physical storage.
DAS has better performance than NAS, especially for compute-intensive software programs. In its barest form, direct-attached storage may involve nothing more than purchasing the drives to be inserted in a server.
However, DAS requires the storage on each device to be separately managed, adding a layer of complexity. Unlike with NAS, DAS does not lend itself to shared storage by multiple users.
NAS vs. SAN
A SAN organizes storage resources on an independent, high-performance network. Network-attached storage handles I/O requests for individual files, whereas a SAN manages I/O requests for contiguous blocks of data.
While NAS traffic moves across Transmission Control Protocol/Internet Protocol (TCP/IP), such as Ethernet, a SAN can route network traffic over the FC protocol designed specifically for storage networks. SANs can also use the Ethernet-based iSCSI protocol instead of FC.
While a NAS can be a single device, a SAN provides full block-level access to a server's disk volumes. Put another way, a client OS will view a NAS as a file system, while a SAN is presented to disk as the client OS.
SAN/NAS Convergence
Until recently, technological barriers have kept the file and block storage worlds separate, each in its own management domain and each with its own strengths and weaknesses. The prevailing view of storage managers was that block storage is first class and file storage is economy class. Giving rise to this notion was a prevalence of business-critical databases housed on SANs.
With the emergence of unified storage, vendors sought to improve large-scale file storage with SAN/NAS convergence. This consolidates block- and file-based data on one storage array. Convergence supports SAN block I/O and NAS file I/O within the same set of switches.
The concept of hyper-convergence first appeared in 2014, pioneered by market leaders Nutanix and SimpliVity Corp. (now part of HPE). Hyper-converged infrastructure (HCI) bundles the computing, network, SDS and virtualization resources on a single appliance. HCI systems pool tiers of different storage media and present it to a hypervisor as a NAS mount point, even though the underlying shared resource is block-based storage. However, a drawback of HCI is that only the most basic file services are provided, meaning a data center may still need to implement a separate network with attached file storage.
Converged infrastructure (CI) packages servers, networking, storage and virtualization resources on sets of hardware prevalidated by the CI vendor. Unlike HCI, which consolidates devices in one chassis, CI consists of separate devices. This gives customers greater flexibility in building their storage architecture. Organizations looking to simplify storage management may opt for CI and HCI systems to replace a NAS or SAN environment.

Comments

Post a Comment

Popular posts from this blog

Black swan

A  black swan event  is an incident that occurs randomly and unexpectedly and has wide-spread ramifications. The event is usually followed with reflection and a flawed rationalization that it was inevitable. The phrase illustrates the frailty of inductive reasoning and the danger of making sweeping generalizations from limited observations. The term came from the idea that if a man saw a thousand swans and they were all white, he might logically conclude that all swans are white. The flaw in his logic is that even when the premises are true, the conclusion can still be false. In other words, just because the man has never seen a black swan, it does not mean they do not exist. As Dutch explorers discovered in 1697, black swans are simply outliers -- rare birds, unknown to Europeans until Willem de Vlamingh and his crew visited Australia. Statistician Nassim Nicholas Taleb uses the phrase black swan as a metaphor for how humans deal with unpredictable events in his 2007...
Post a Comment
Read more

A Graphics Processing Unit (GPU)

A graphics processing unit (GPU) is a computer chip that performs rapid mathematical calculations, primarily for the purpose of rendering images. A GPU may be found integrated with a central processing unit (CPU) on the same circuit, on a graphics card or in the motherboard of a personal computer or server. In the early days of computing, the CPU performed these calculations. As more graphics-intensive applications such as AutoCAD were developed; however, their demands put strain on the CPU and degraded performance. GPUs came about as a way to offload those tasks from CPUs, freeing up their processing power. NVIDIA, AMD, Intel and ARM are some of the major players in the GPU market. GPU vs. CPU A graphics processing unit is able to render images more quickly than a central processing unit because of its parallel processing architecture, which allows it to perform multiple calculations at the same time. A single CPU does not have this capability, although multi...
Post a Comment
Read more

6G (sixth-generation wireless)

6G (sixth-generation wireless) is the successor to 5G cellular technology. 6G networks will be able to use higher frequencies than 5G networks and provide substantially higher capacity and much lower latency. One of the goals of the 6G Internet will be to support one micro-second latency communications, representing 1,000 times faster -- or 1/1000th the latency -- than one millisecond throughput. The 6G technology market is expected to facilitate large improvements in the areas of imaging, presence technology and location awareness. Working in conjunction with AI, the computational infrastructure of 6G will be able to autonomously determine the best location for computing to occur; this includes decisions about data storage, processing and sharing.  Advantages of 6G over 5G 6G is expected to support 1 terabyte per second (Tbps) speeds. This level of capacity and latency will be unprecedented and wi...
Post a Comment
Read more