In recent years, the number of vendors offering online data storage for both consumers and businesses has increased dramatically. Some services store only a particular kind of data, such as photos, music or backup data, while others will allow users to store any type of file. Most of these vendors offer a small amount of storage for free with additional storage capacity available for a fee, usually paid on a monthly or annual basis.

One of the biggest benefits of online storage is the ability to access data from anywhere. As the number of devices the average person uses continues to grow, syncing or transferring data among devices has become more important. Not only does it help transfer data between devices, online data storage also provides the ability to share files among different users. This is particularly helpful for business users, although its also popular with consumers who want to share photos, videos and similar materials with their friends and family.

Online data storage also offers distinct advantages for backup and disaster recovery situations because its located off site. In a fire, flood, earthquake or similar situation, on-site backups could be damaged, but online backups wont be affected unless the disaster is very widespread.

However, online data storage does have some potential downsides. Some people worry about the security of cloud storage services, and some vendors have experienced significant outages from time to time, leading to concerns about reliability.

Before the development of the Internet, computer systems were limited to local storage or portable storage, first in the form of tapes and floppy disks, then CDs, DVDs and USB thumb drives. Generally, using on-site storage is faster than using Internet storage, because you dont have to wait for files to upload or download. However, on-site storage is more susceptible to loss due to theft, natural disasters or device failure. By contrast, most online data storage facilities offer enhanced physical security and automated backup capabilities to ensure that data is not lost. Online data storage also enables easier data transfer and sharing.

Like local storage, portable storage devices offer fast data transfer along with some data transfer and sharing capabilities. However, portable storage isnt quite as convenient as online data storage, particularly if you want to share files with a large number of users. Portable storage devices are also easy to lose or damage, and they offer limited storage capacity.

Recently, the term cloud storage has become increasingly common. Although many people use the terms "cloud storage" and "online storage" interchangeably, technically, cloud storage is a particular kind of online data storage. In order to be considered cloud storage, a service must be sold on demand, provide elasticity (the user can have as much or as little as desired) and offer self-service capabilities.

Many individuals and organizations use a mix of on-site and online storage capabilities. For example, they might use local storage for files they use frequently and online storage for backup or archive data. Or they might use local storage for personal data and online storage for files that they wish to share with others.

In most cases, setting up online data storage is incredibly easy, but the exact process will depend on the vendor. For most consumer online storage services, the process entails nothing more than setting up an account with a user name and password, although in some cases users will also need to download and install some software. Using these online data storage services is also very simple, and many offer intuitive drag-and-drop interfaces. Again, the exact details vary by vendor.

For business-oriented online storage services, the set up and use procedures can be slightly more complex because they generally offer more options for configuration, security and reliability. However, because they want to appeal to as many customers as possible, enterprise vendors generally make their services as easy to use and maintain as possible.

Amazon is making a big move in the cloud storage space with a recent decision to bring unlimited cloud storage to Cloud Drive customers.

The e-commerce company announced March 26 that its rolling out two plans designed to provide secure storage for users existing content while also allowing them to automatically upload unlimited amounts of videos, music, photos, movies, and files to the cloud.

Customers with vast photo collections can choose the Unlimited Photos Plan, which will cost $11.99 per year, or less than $1 per month. This option provides endless photo storage in Cloud Drive and also includes 5GB of extra storage space for videos and other documents.

For those with greater storage needs, Amazon is offering the Unlimited Everything Plan, which allows storage of new and existing documents, photos, videos, and music for $59.99 per year.

"Most people have a lifetime of birthdays, vacations, holidays, and everyday moments stored across numerous devices. And, they dont know how many gigabytes of storage they need to back all of them up," said Amazon Cloud Drive director Josh Petersen in the companys announcement. "With the two new plans we are introducing today, customers dont need to worry about storage space – they now have an affordable, secure solution to store unlimited amounts of photos, videos, movies, music, and files in one convenient place."

Both plans will be available for free three-month trial periods before their payment plans kick in. Amazon Prime customers and owners of the Kindle Fire, who already have access to unlimited photo storage, can choose to upgrade their plan. Current customers of Cloud Drive can switch plans via their account page.

This announcement makes Amazon a stiff competitor in the ever-growing cloud space, which is crowded with providers like Google, Apple, Dropbox, and Microsoft, battling for market share with cheap storage. Amazons endless storage will likely prove a tempting option for consumers with ever-growing piles of digital documents.

According to the Dictionary Industry Association storage networks (and who should know better?):

Storage Area Network (SAN) is a high-performance network, which is to enable the storage devices to communicate with computer systems and with each other primary purpose.

We believe that the things most interesting about this definition is not what he says:

It does not say that the only purpose for SAN is communication between computers and storage. Many organizations are working on a removable storage area networks completely to life, which sometimes carry traffic management application and others.

It does not say that the SAN uses Ethernet or Fibre Channel or any other specific link technology. There is a growing number of networking technologies have architectural and physical properties that make them suitable for use in storage areas.

He did not say what kind of interconnected storage devices. Whole disk and tape drives and subsystems RAID and robotic libraries, and file servers used fruitfully in SAN environments today. One of the exciting aspects of the SAN technology is that it is encouraging the development of new types of storage devices that provide new benefits for users. Some of these are undoubtedly in the market, but fail those that succeed will make lasting improvements in the way in which digital information is stored and processed.

Lets dig a little deeper in this definition.

What makes a different SAN?

Anyone in the field of information technology is already well known that the computers are connected to the storage devices. If this is the SAN everything he does, all that is new or different about it? The answer is simple, we will keep coming back to again and again throughout this book:

Global Storage Connectivity

Is connected computers to actually store the day, but all of the computers to install and connect all of its storage? This is the fundamental point about the storage-area networks come into contact with a lot of computers to a lot of storage devices, enabling computers to negotiate device ownership among them and, ideally, to exchange data. If there is one hallmark of SANs, its global connectivity to storage devices and computers.

To estimate the value of the storage universal plug, look at the client computer / traditional server system shown in Figure 1.1.

Figure 1.1

Figure islands of information / Server 1.1 client

From this image, business as usual computing client / server, it is immediately apparent that through the deployment of multiple servers, an organization that creates an interconnected islands of information automatically. Each island can be accessed via a single computer, but not others. If computer B needs to use the data produced by computer A, the data has to be copied to computer B.

There are many techniques to transfer data between computers: backup, file transfer. And communication between processes, for example, is not limited. But the real issue is that the organization of information services have to own and manage the additional resources required both to copy the data from computer to computer B and stored in both locations. There is no reason for this to work duplication of effort, and others that the computer needs data that has been produced by another computer.

There are more serious implication of information which depend on regular copying of data from one computer to another treatment strategy. Often forced computers that access to copy the data to work with the data outdated simply because it is physically impossible to make a copy in a timely manner. Moreover, the additional operational complexity introduced by the need to copy data between servers creates an additional opportunity to expensive mistakes.

By contrast with the system architecture and distributed based SAN shown in Figure 1.2.

Figure 1-2

Figure 1.2 SAN eliminates islands of information

With SAN, and the concept of a host computer and one that has the data stored or not meaningful. All servers in Figure 1.2 of a physical link to all storage devices. If F server needs the data that was produced by E server, there is no need to copy, because the server F can be accessed on any hardware E Data Storage Server. All that is required is a change of ownership of logical storage device from server to server EF or better yet, to pre-E server agreement to stay out of the way while actively use the data server F.

Mass storage unit connection has some very powerful effects circuits information services:

Theres no need to set a timetable middle of the data transfer between pairs of servers.

Theres no need to purchase and maintain additional storage to organize one server data temporarily in another server.

Theres no need to worry about whether they are synchronized copies of the data that is used by the two computers running different applications (which is exactly the same content), because the computers are working from the same copy of the data.

In fact, at this level simplistic, it is difficult to see how any organization responsible for electronic information processing can not be that he wants SAN. Lets dig deeper still and see how true this is.

What makes a good SAN?

SAN architecture completely interconnected appear on the right side of Figure 1.2 intuitively attractive, but if I want her to be the backbone of I / O to process information services, it needs a couple of qualities:

There must be a SAN is available too. SAN and one connecting all the computers for all storage puts a lot of eggs access to company information in one basket. SAN to be the best non very destruction or institution can be literally out of business. SAN good implementation will have built-in protection from just about any type of failure imaginable. As we will see in later chapters, this means that not only must the links and keys infrastructure consists SAN be able to survive the failure element, but storage devices, and interfaces to the tongue, and computers themselves, and we must all have built-in strategies to survive and recover from failures also .

I / O performance for SAN must grow or scale as the number of connected devices is growing. If SAN connects a lot of computers and plenty of storage, it may be better able to deliver the performance they all need to do their jobs, including one at a time. The best SAN delivers both high and low data I / O request latency transfer rates. Moreover, it must be the performance of SAN and able to grow as the organization of information and processing needs grow storage. As is the case with the networks of other companies, it is not just a process to replace SAN often.

On the positive side, a SAN to do the scope of the additional application and provides enhanced performance by separating Size-high I / O traffic from the message traffic client / server, and give each track is optimized for its properties and eliminate cross-talk between them.

Investment required to implement high-SAN, both in terms of direct cost of capital or in terms of the time needed to learn the technology and design, deploy, and melody, and SAN management and energy. Any institution is well managed to do cost-benefit analysis before deciding to implement storage networks. The results of this analysis suggests it is almost certain that the largest yield comes from the use of SAN to connect the most important enterprise data to computers that are running the most important applications.

But the most important data is the data that can least afford institution to be without. Together, the natural desire to maximize the return on investment and the importance of operational data lead to Article 1 of the storage networking:

When designing SAN access to critical corporate data, make sure SAN available too (ie can survive the failure of all of the ingredients in it, and components associated with it) and make sure it can grow beyond the needs peak expected performance without interruption.

What Makes a Great SAN?

Therefore, a key feature of the storage areas are the global connectivity data storage. Comprehensive connectivity enables a range of important advantages. Depending on the particular SAN hardware and software components selected, additional benefits may be realized from the advanced functions are being built in the SAN devices today. Again, we describe some of the features and benefits identified in later, but for now affirm Article 2 of storage networks:

When assessing the implementation SAN options, once can be achieved capacity, availability, and the requirements of the basic performance, and the search for advanced functions available in the architecture selected and look at how they can be used to further reduce the cost or enhance the information provided to users services.