Data storage refers to magnetic, optical, or mechanical media that records and preserves digital information for ongoing or future operations.
There are two types of digital information: input and output data. Users provide the input data. Computers provide output data. But a computer's CPU can't compute anything or produce output data without the user's input.
Users can enter the input data directly into a computer. However, they have found early on in the computer-era that continually entering data manually is time- and energy-prohibitive. One short-term solution is computer memory, also known as random access memory (RAM). But its storage capacity and memory retention are limited. Read-only memory (ROM) is, as the name suggests, the data can only be read but not necessarily edited. They control a computer's basic functionality.
Although advances have been made in computer memory with dynamic RAM (DRAM) and synchronous DRAM (SDRAM), they are still limited by cost, space, and memory retention. When a computer powers down, so does the RAM's ability to retain data. The solution? Data storage.
With data storage space, users can save data onto a device. And should the computer power down. The data is retained. And instead of manually entering data into a computer, users can instruct the computer to pull data from storage devices. Computers can read input data from various sources as needed, and it can then create and save the output to the same sources or other storage locations. Users can also share data storage with others.
Today, organizations and users require data storage to meet today's high-level computational needs like big data projects, artificial intelligence (AI), machine learning and the Internet of Things (IoT). And the other side of requiring huge data storage amounts is protecting against data loss due to disaster, failure or fraud. So, to avoid data loss, organizations can also employ data storage as backup solutions.
In simple terms, modern computers, or terminals, connect to storage devices either directly or through a network. Users instruct computers to access data from and store data to these storage devices. However, at a fundamental level, there are two foundations to data storage: the form in which data is takes and the devices the data is recorded and stored on.
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To store data, regardless of form, users need storage devices. Data storage devices come in two main categories: direct area storage and network-based storage.
Direct area storage, also known as direct-attached storage (DAS), is as the name implies. This storage is often in the immediate area and directly connected to the computing machine accessing it. Often, it's the only machine connected to it. DAS can provide decent local backup services, too, but sharing is limited. DAS devices include diskettes, optical discs—compact discs (CDs) and digital video discs (DVDs)—hard disk drives (HDD), flash drives and solid-state drives (SSD).
Network-based storage allows more than one computer to access it through a network, making it better for data sharing and collaboration. Its off-site storage capability also makes it better suited for backups and data protection. Two common network-based storage setups are network-attached storage (NAS) and storage area network (SAN).
NAS is often a single device that is made up of redundant storage containers or a redundant array of independent disks (RAID). SAN storage can be a network of multiple devices of various types, including SSD and flash storage, hybrid storage, hybrid cloud storage, backup software and appliances, and cloud storage. Here are how NAS and SAN differ:
NAS
- Single storage device or RAI
- File storage system
- TCP/IP Ethernet network
- Limited users
- Limited speed
- Limited expansion options
- Lower cost and easy setup
SAN
- Network of multiple devices
- Block storage system
- Fibre Channel network
- Optimized for multiple users
- Faster performance
- Highly expandable
- Higher cost and complex setup
Flash storage is a solid-state technology that uses flash memory chips for writing and storing data. A solid-state disk (SSD) flash drive stores data using flash memory. Therefore, compared to HDDs, a solid-state system has no moving parts and less latency, so fewer SSDs are needed. Since most modern SSDs are flash-based, flash storage is synonymous with a solid-state system.
SSDs and flash offer higher throughput than HDDs, but all-flash arrays can be more expensive. Many organizations adopt a hybrid approach, mixing the speed of flash with the storage capacity of hard disk drives. A balanced storage infrastructure enables companies to apply the right technology for different storage needs. It offers an economical way to transition from traditional HDDs without going entirely to flash.
Cloud storage delivers a cost-effective, scalable alternative to storing files to on-premises hard disks or storage networks. Cloud service providers allow you to save data and files in an off-site location that you can access through the public internet or a dedicated private network connection. The provider hosts, secures, manages, and maintains the servers and associated infrastructure and ensures that you have access to the data whenever you need it.
Hybrid cloud storage combines private and public cloud elements. With hybrid cloud storage, organizations can choose which cloud to store data. For instance, highly regulated data subject to strict archiving and replication requirements is usually more suited to a private cloud environment. Whereas less sensitive data can be stored in the public cloud. Some organizations use hybrid clouds to supplement their internal storage networks with public cloud storage.
Backup storage and appliances protect data loss from disaster, failure, or fraud. They make periodic data and application copies to a separate, secondary device and then use those copies for disaster recovery. Backup appliances range from HDDs and SSDs to tape drives to servers, but backup storage can also be offered as a service, also known as backup-as-a-service (BaaS). Like most as-a-service solutions, BaaS provides a low-cost option to protect data, saving it in a remote location with scalability.
Data can be recorded and stored in three main forms: file storage, block storage, and object storage.
File storage, also called file-level or file-based storage, is a hierarchical storage methodology that is used to organize and store data. In other words, data is stored in files, the files are organized in folders and the folders are organized under a hierarchy of directories and subdirectories.
Block storage, sometimes referred to as block-level storage, is a technology that is used to store data into blocks. The blocks are then stored as separate pieces, each with a unique identifier. Developers favor block storage for computing situations that require fast, efficient, and reliable data transfer.
Object storage, often referred to as object-based storage, is a data storage architecture for handling large amounts of unstructured data. This data doesn't conform to, or can't be organized easily into, a traditional relational database with rows and columns. Examples include email, videos, photos, web pages, audio files, sensor data, and other types of media and web content (textual or nontextual).
Computer memory and local storage might not provide enough storage, storage protection, multiple users' access, speed, and performance for enterprise applications. So, most organizations employ some form of a SAN in addition to a NAS storage system.
SAN
Sometimes referred to as the network behind the servers, a SAN is a specialized, high-speed network that attaches servers and storage devices. It consists of a communication infrastructure, which provides physical connections, allowing an any-to-any device to bridge across the network using interconnected elements, such as switches and directors. The SAN can also be viewed as an extension of the storage bus concept. This concept enables storage devices and servers to interconnect by using similar elements, such as local area networks (LANs) and wide-area networks (WANs). A SAN also includes a management layer that organizes the connections, storage elements and computer systems. This layer ensures secure and robust data transfers.
Traditionally, only a limited number of storage devices might attach to a server. Alternatively, a SAN introduces networking flexibility enabling one server, or many heterogeneous servers across multiple data centers, to share a common storage utility. The SAN also eliminates the traditional dedicated connection between a server and storage and the concept that the server effectively owns and manages the storage devices. So, a network might include many storage devices, including disks, magnetic tape, and optical storage. And the storage utility might be located far from the servers that it uses.
SAN components
The storage infrastructure is the foundation on which information relies. Therefore, the storage infrastructure must support the company's business objectives and business model. A SAN infrastructure provides enhanced network availability, data accessibility and system manageability. In this environment, simply deploying more and faster storage devices is not enough. A good SAN begins with a good design.
The core components of a SAN are Fibre Channel, servers, storage appliances, and networking hardware and software.
The first element to consider in any SAN implementation is the connectivity of the storage and server components, which typically use Fibre Channel. SANs, such as LANs, interconnect the storage interfaces together into many network configurations and across longer distances.
The server infrastructure is the underlying reason for all SAN solutions, and this infrastructure includes a mix of server platforms. With initiatives, such as server consolidation and Internet commerce, the need for SANs increases, making the importance of network storage greater.
A storage system can consist of disk systems and tape systems. The disk system can include HDDs, SSDs, or Flash drives. The tape system can include tape drives, tape autoloaders and tape libraries.
SAN connectivity consists of hardware and software components that interconnect storage devices and servers. Hardware can include hubs, switches, directors, and routers.
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