What is Data ?

Data is a collection of raw facts from which conclusions may be drawn.Handwritten letters, a printed book, a family photograph, a movie on video tape, printed and duly signed copies of mortgage papers, a bank’s ledgers, and an account holder’s passbooks are all examples of data.Today, the same data can be converted into more convenient forms such as an

e‑mail message, an e-book, a bitmapped image, or a digital movie. This data can be generated using a computer and stored in strings of 0s and 1s, as shown in Figure

Types Of Data:

Data can be classified as structured or unstructured based on how it is stored and managed. Structured data is organized in rows and columns in a rigidly defined format so that applications can retrieve and process it efficiently. Structured data is typically stored using a database management system (DBMS).Data is unstructured if its elements cannot be stored in rows and columns,and is therefore difficult to query and retrieve by business applications. For example, customer contacts may be stored in various forms such as sticky notes, e-mail messages, business cards, or even digital format files such as .doc, .txt,

and .pdf. Due its unstructured nature, it is difficult to retrieve using a customer relationship management   application. Unstructured data may not have the required components to identify itself uniquely for any type of processing or     interpretation. Businesses are primarily concerned with managing unstructured data because over 80 percent of enterprise data is unstructured and requires significant storage space and effort to manage.

What is Storage?

Data created by individuals or businesses must be stored so that it is easily accessible for further processing. In a computing environment, devices designed for storing data are termed storage devices or simply storage. The type of storage used varies based on the type of data and the rate at which it is created and used. Devices such as  memory in a cell phone or digital camera, DVDs, CD-ROMs, and hard disks in personal computers are examples of storage devices. Businesses have several options available for storing data including internal hard disks, external disk arrays and tapes.

Evolution of Storage Technology and Architecture

Organizations had centralized computers (mainframe) and information storage devices (tape reels and disk packs) in their data center. The evolution of open systems and the affordability and ease of deployment that they offer made it possible for business units/departments to have their own servers and storage. In earlier implementations of open systems, the storage was typically internal to the server.

■ Redundant Array of Independent Disks (RAID): This technology was developed to address the cost, performance, and availability requirements of data. It continues to evolve today and is used in all storage architectures such as DAS, SAN, and so on.

■Direct-attached storage (DAS): This type of storage connects directly to a server (host) or a group of servers in a cluster. Storage can be either internal or external to the server. External DAS alleviated the challenges of limited internal storage capacity.

■ Storage area network (SAN): This is a dedicated, high-performance Fibre Channel (FC) network to facilitate block-level communication between servers and storage. Storage is partitioned and assigned to a server for accessing its data. SAN offers scalability, availability, performance, and cost benefits compared to DAS.

■Network-attached storage (NAS): This is dedicated storage for file serving applications. Unlike a SAN, it connects to an existing communication network (LAN) and provides file access to heterogeneous clients. Because it is purposely built for providing storage to file server applications, it offers higher scalability, availability, performance, and cost benefits compared

to general purpose file servers.

■ Internet Protocol SAN (IP-SAN): One of the latest evolutions in storage architecture, IP-SAN is a convergence of technologies used in SAN and NAS. IP-SAN provides block-level communication across a local or wide area network (LAN or WAN), resulting in greater consolidation and availability of data.

What is Data Center ?

Organizations maintain data centers to provide centralized data processing capabilities across the enterprise. Data centers store and manage large amounts of mission-critical data. The data center infrastructure includes computers, storage systems, network devices, dedicated power backups, and environmental controls (such as air conditioning and fire suppression).

Large organizations often maintain more than one data center to distribute data processing workloads and provide backups in the event of a disaster. The storage requirements of a data center are met by a combination of various storage architectures.

■Application: An application is a computer program that provides the logic for computing operations. Applications, such as an order processing system, can be layered on a database, which in turn uses operating system services to perform read/write operations to storage devices.

■Database: More commonly, a database management system (DBMS) provides a structured way to store data in logically organized tables that are interrelated. A DBMS optimizes the storage and retrieval of data.

■ Server and operating system: A computing platform that runs applications and databases.

■Network: A data path that facilitates communication between clients and servers or between servers and storage.

■ Storage array: A device that stores data persistently for subsequent use.  These core elements are typically viewed and managed as separate entities, but all the elements must work together to address data processing requirements.