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Sunday, 2 October 2016

Introduction to Storage

     Today, the data can be converted into more convenient forms, such as an e-mail message, an e-book, a digital image, or a digital movie. This data can be generated using a computer and stored as strings of binary numbers (0s and 1s), as shown in given below figure. Data in this form is called digital  data and is accessible by the user only after a computer processes it.

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, which makes it difficult to query and retrieve by applications. For example, customer contacts that are 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 to its unstructured nature, it is difficult to retrieve this data using a traditional customer relationship management application. A vast majority of new data being created today is unstructured.

Big Data
     Data which are very large in size is called Big Data. Normally we work on data of the size Mega Bytes (MB) [Word Doc, Excel etc.] or maximum Giga Bytes (GB) [Movies, Songs etc.] but data in Peta Bytes (PB) size is called Big data. It includes both structured and unstructured data generated by a variety of sources, including business application transactions, web pages, videos, images, e-mails, social media, and so on. These data comes from many sources like
1. Social Networking Sites
     Facebook, Google, LinkedIn all these sites generates huge amount of data on a day to day basis as they have billions of users world wide.

2. E-Commerce Site
     Sites like Amazon, Flipkart, Snapdeal generates huge amount of logs from which users buying trends can be traced.

3. Weather Station
     All the weather station and satellite gives very huge data which are stored and manipulated to forecast weather.

4. Telecom Company
     Telecom giants like Airtel, Vodafone study the user trends and accordingly publish their plans and for this they store the data of its million users.

5. Share Market
     Stock exchange across the world generates huge amount of data through its daily transaction.

6. Search Engine Data
     Search engines retrieve lots of data from different databases.

     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 a media card in a cell phone or digital camera, DVDs, CD-ROMs, and disk drives 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 Architecture
     Historically, organizations had centralized computers (mainframes) and information storage devices (tape reels and disk packs) in their data center. In earlier implementations of open systems, the storage was typically internal to the server. These storage devices could not be shared with any other servers. This approach is referred to as server-centric storage architecture. In this architecture, each server has a limited number of storage devices, and any administrative tasks, such as maintenance of the server or increasing storage capacity, might result in unavailability of information.

     To overcome these challenges, storage evolved from server-centric to information-centric architecture. In this architecture, storage devices are managed centrally and independent of servers. These centrally-managed storage devices are shared with multiple servers. When a new server is deployed in the environment, storage is assigned from the same shared storage devices to that server. The capacity of shared storage can be increased dynamically by adding more storage devices without impacting information availability. In this architecture, information management is easier and cost-effective.

Next Tutorial  Data Center Infrastructure Tutorial

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