A Storage Area Network is a high-speed sub network of shared storage devices. A SAN’s architecture works in a way that makes all storage devices available to all servers on a LAN or WAN. A Storage Area Network can be anything from two servers on a network accessing a central pool of storage devices to several thousand servers accessing many millions of megabytes of storage. Show
A SAN(Storage Area Network) is a network specifically dedicated to the task of transporting data for storage and retrieval. It is an alternative for storing data on disks directly attached to servers which are connected through general purpose networks. SAN uses special switches like director switch or Network Interface Cards as a mechanism to connect the devices in network. Currently, SANs are implemented using communication protocols such as ISCSI, ESCON, or FCIP. SAN comes into focus when there is need for a effective disaster recovery processes by using RAID technology. SANs support disk mirroring, backup and restore, archival and retrieval of archived data, data migration from one storage device to another and the sharing of data among different servers in a network. SANs can incorporate subnetworks with network-attached storage (NAS) systems. Storage Area Networks SAN technology is similar but distinct from network attached storage (NAS) technology. While SANs traditionally employ low-level network protocols for transferring disk blocks, a NAS device typically works over TCP/IP and can be integrated fairly easily into home computer networks. A SAN infrastructure uses special Fiber Channels dedicated to data storage which offers fast data transfer speeds combined with a high level of efficiency. It also Provides `real time’ access to data across the network. Storage Area Networks allow storage devices to exist on their own separate network and communicate directly with each other over very fast media. SANs address the bandwidth bottlenecks commonly associated with LAN-based server storage and the scalability limitations found with SCSI bus based implementations. Read More: SAN Continue Learning about Computer Science What lets you communicate with your computer?input devices. What connects two different networks?Two different networks are connected by a router. Switches are used to connect network devices within networks. Interface devices communicate with the computer through input and output units What are these interface devices called?Peripherals A computer can access devices on the same network but can not access devices on other networks What is the probable problem?Incorrect default gateway. What intermediary devices could be used to implement security between networks?firewall What is 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. NAS stands out for its ease of access, high capacity and low cost. The devices consolidate storage in one place and support a cloud tier and tasks, such as archiving and backup. 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 is network-attached storage used for?The purpose of NAS is to enable users to collaborate and share data more effectively. It is useful to distributed teams that need remote access or work in different time zones. NAS connects to a wireless router, making it easy for distributed workers to access files from any desktop or mobile device with a network connection. Organizations commonly deploy a NAS environment as the foundation for a personal or private cloud. Some NAS products are designed for use in large enterprises. Others are 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 file servers. To expand storage capacity, NAS appliances are outfitted with more or larger disks, known as scale-up NAS. Appliances are also 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 systems use faster flash storage, either as a tier alongside HDDs or in all-flash configurations. With a NAS system, distributed work environments can easily access files and folders from any network-connected device.NAS use cases and examplesThe applications to be used determine the type of HDD selected for a NAS device. Sharing Microsoft Excel spreadsheets or Word documents with co-workers is a routine task, as is performing periodic data backup. Conversely, using NAS to handle large volumes of streaming media files requires larger capacity disks, more memory and more powerful network processing. At home, people use a NAS system to store and serve multimedia files and to automate backups. Home users rely on NAS to do the following:
In the enterprise, NAS is used:
An example of how enterprises use the technology is when a company imports many images every day. The company cannot stream this data to the cloud because of latency. Instead, it uses an enterprise-class NAS to store the images and cloud caching to maintain connections to the images stored on premises. Higher-end NAS products have enough disks to support redundant array of independent disks, or RAID, which is a storage configuration that turns multiple hard disks into one logical unit to boost performance, high availability and redundancy. Netgear is one of several popular NAS vendors.NAS product categoriesNAS devices are grouped in three categories based on the number of drives, drive support, drive capacity and scalability. High-end or enterpriseThe high end of the market is driven by organizations that need to store vast quantities of file data, including virtual machine (VM) images. Enterprise devices provide rapid access and clustering capabilities. The clustering concept addresses drawbacks associated with traditional NAS. For example, one device allocated to an organization's primary storage space creates a potential single point of failure. Spreading mission-critical applications and file data across multiple boxes and adhering to scheduled backups decrease the risk. Clustered NAS systems also reduce NAS sprawl. A distributed file system runs concurrently on multiple NAS devices. This approach provides access to all files in the cluster, regardless of the physical node on which it resides. MidmarketThe midmarket accommodates businesses that require several hundred terabytes (TB) of data. These devices cannot be clustered, however, which can lead to file system siloes if multiple NAS devices are required. Low-end or desktopThe low end is aimed at home users and small businesses that require local shared storage. This market is shifting toward a cloud services model, with products such as Buurst's SoftNAS Cloud and software-defined storage (SDS) from legacy storage vendors. Find out about the three basic types of NAS systems: low-end, midmarket and high-end NAS.NAS deployments for businessThe chart below describes five different ways network-attached storage can be deployed and lists the pros and cons for each approach. Each deployment can easily be managed by a single network manager. The different deployment approaches include:
What's the future of network-attached storage?The baseline functionality of NAS devices has broadened to support virtualization. High-end NAS products may also support data deduplication, flash storage, multiprotocol access and data replication. Some NAS devices run a standard operating system, such as Microsoft Windows, while others run a vendor's proprietary OS. IP is the most common data transport protocol, but some midmarket NAS products may support additional protocols, such as:
Additionally, high-end NAS devices may support Gigabit Ethernet for even faster data transfer across the network. Some larger enterprises are switching to object storage for capacity reasons. However, NAS devices are expected to continue to be useful for small and medium-sized businesses. Scale-up and scale-out NAS vs. object storageScale-up and scale-out are two versions of NAS. Object storage is an alternative to NAS for handling unstructured data. Scale-up NASIn a network-attached storage deployment, the NAS head is the hardware that performs the control functions. It provides access to back-end storage through an internet connection. This configuration is known as scale-up architecture. A two-controller system expands capacity with the addition of drive shelves, depending on the scalability of the controllers. Scale-out NASWith scale-out systems, the storage administrator installs larger heads and more hard disks to boost storage capacity. Scaling out provides the flexibility to adapt to an organization's business needs. Enterprise scale-out systems can store billions of files without the performance tradeoff of doing metadata searches. Object storageSome industry experts speculate that object storage will overtake scale-out NAS. However, it's possible the two technologies will continue to function side by side. Both storage methodologies deal with scale, but in different ways. NAS files are centrally managed via the Portable Operating System Interface (POSIX). It provides data security and ensures multiple applications can share a scale-out device without fear that one application will overwrite a file being accessed by other users. Object storage is a new method for easily scalable storage in web-scale environments. It is useful for unstructured data that is not easily compressible, particularly large video files. Object storage does not use POSIX or any file system. Instead, all the objects are presented in a flat address space. Bits of metadata are added to describe each object, enabling quick identification within a flat address namespace. NAS vs. DASDirect-attached storage (DAS) refers to a dedicated server or storage device that is not connected to a network. A computer's internal HDD is the simplest example of DAS. To access DAS files, the user must have access to the physical storage. DAS has better performance than NAS, especially for compute-intensive software programs. In its barest form, DAS may be nothing more than the drives that go in a server. With DAS, the storage on each device must be separately managed, adding a layer of complexity. Unlike NAS, DAS does not lend itself well to shared storage by multiple users. See how SAN, DAS and NAS platforms compare.NAS vs. SANWhat are the differences between SAN and NAS? 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. See how NAS and SAN compare.NAS traffic moves across Transmission Control Protocol/Internet Protocol, such as Ethernet. SAN, on the other hand, routes network traffic over the Fibre Channel (FC) protocol designed specifically for storage networks. SANs can also use the Ethernet-based Internet Small Computer System Interface (iSCSI) protocol instead of FC. While 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 NAS as a file system, while a SAN appears to the disk as the client OS.
SAN/NAS convergenceUntil recently, technological barriers have kept the file and block storage worlds separate. Each has had its own management domain and 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 in 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 Hewlett Packard Enterprise (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. They do this 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. That means 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 hardware that the vendor has prevalidated. Unlike HCI, which consolidates devices in one chassis, CI is separate devices. This gives customers greater flexibility in building their storage architecture. Organizations looking to simplify storage management may opt for CI or HCI systems to replace a NAS or SAN environment. NAS and file storage vendorsDespite the growth in flash storage, NAS systems still primarily rely on spinning media. The list of vendors is extensive, with most offering more than one configuration to help customers balance capacity and performance. NAS systems come fully populated with disks or as a diskless chassis where customers add HDDs from their preferred vendor. Drive-makers Seagate Technology, Western Digital and others work with NAS vendors to develop and qualify media. Vendors of NAS appliances or scalable file storage include the following:
Cloud-based file storageIn addition to NAS devices, some data centers augment or replace physical NAS with cloud-based file storage. Amazon Elastic File System is the scalable storage in Amazon Elastic Compute Cloud. Similarly, Microsoft Azure File Service furnishes managed file shares based on SMB and CIFS that local and cloud-based deployments can use. Not as common now, NAS gateways formerly enabled files to access externally attached storage, either connecting to a high-performance area network over FC or just a bunch of disks in attached servers. NAS gateways are still in use, but less frequently; customers are more likely to use a cloud storage gateway, object storage or scale-out NAS. A cloud gateway sits at the edge of a company's data center network, shuttling applications between local storage and the public cloud. Nasuni Corp. created the cloud-native UniFS file system software, bundled on Dell PowerEdge servers or available as a virtual storage appliance. Nasuni rival Panzura provides a similar service with its Panzura CloudFS file system and Freedom Filer cache appliances. Learn more about five key benefits of cloud storage: scalability, flexibility, multi-tenancy, simpler data migration and lower cost disaster recovery. What is a distinct network of storage devices?A storage area network (SAN) is a dedicated network of storage devices used to provide a pool of shared storage that multiple computers and servers can access.
Is a network of storage devices that communicate directly with each other and with other networks?NAS is appropriate for enterprises that require not only fault tolerance, but also fast access for their data. It is a distinct network of storage devices that communicate directly with each other and with other networks. Multiple storage devices are connected to multiple, identical servers.
What is a specialized storage device or group of storage devices that provides centralized fault tolerant data storage for a network?A specialized storage device or group of storage devices that provides centralized fault-tolerant data storage for a network. NAS depends on traditional network transmission methods such as Ethernet.
What do you call a collection of devices connected to each other to share information?Computer network. A collection of computers and other hardware devices that are connected together to share hardware, software, and data, as well as to communicate electronically with one another.
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