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What is the Concept of NAS (Network-attached Storage) And SAN (Storage Area Networks)?

What is the Concept of NAS (Network-attached Storage) And SAN (Storage Area Networks)? : Today I will discuss about this topic that what is NAS & SAN? What is the difference between NAS & SAN? What is important role of NAS & SAN in the optical network?Today's e-business environment is driven by the data and information explosion fueled by the growth of the Internet, the popularity of dataintensive multimedia technologies, and the focus on server and storage consolidation. Server farms represent critical components in many IT infrastructures such that customers must implement comprehensive and flexible storage solutions to enhance and ensure effective and timely backup and restore capabilities.

The SAN technology has evolved from independent hardware and software products to becoming a package where many different elements can be assembled to provide a comprehensive storage solution. Effective data storage is a critical component of successful business planning. The corporations, with no business tolerance for downtime, are working
towards achieving a state of business continuity where critical systems and networks are continuously available no matter what happens. NAS systems are networked appliances which contain one or more storage drives, often arranged into logical, redundant storage containers or RAID. Network-attached storage removes the responsibility of file serving from other servers on the network.
Network-attached Storage (NAS) Device
What is the Concept of NAS (Network-attached Storage) And SAN (Storage Area Networks)?
The trends that originally motivated the creation of Fibre Channel have continued or accelerated. The speed of processors; the capacities of memory, disks, and tapes; and the use of switched communications networks have all been doubling every 18 to 24 months with the doubling period steadily shortening slightly. However,the rate of I/O improvement has been much slower, so that devices are even more I/O limited. The continuing observation is that computers usually appear nearly instantaneous, except when doing I/O (downloading web pages), or managing stored data (backing up file systems).

Goal of the Fiber Channel and the SAN is to:
Optimize the movement of data between server and storage systems,
Manage the data and access to data, so that communications are optimized as much as possible, while continuously and reliably providing access to data SAN versus LAN.

SAN versus NAS

Many IT organizations are contemplating network implementations that revolve around storage networks. The two prevalent terms that exist in the marketplace are SAN (Storage Area Networks) and NAS (Network-attached Storage). The two concepts are different in their network implementations and advantages and disadvantages exist for both approaches. The debate is still on as to which implementation will prevail.


Network-attached Storage grew out of the concept of file servers managing the files for clients on the network. This approach achieved tremendous success through products such as NetWare and Microsoft Windows NT Server. With file servers, large amounts of storage could be connected from the server and served to users on a file-by-file basis, while management and backup of that data could be centralized off the server. Over time it became clear that a full network operating system was not necessary for file services. This
resulted in vendors designing a specialized server and operating.system called a storage appliance which could be put on a network to provide the storage functions.


Storage Area Networks emerged from the concept of taking storage devices and storage heavy traffic and creating a separate back-end network designed specifically for that type of traffic. Separating ownership of a server from its storage, and placing all the storage devices directly on a Fiber Channel network, allows a many-to-many connection from servers to storage and from storage to other storage devices. This approach grants the benefits of increased scalability, availability, and performance. In addition, backups can be done without affecting the rest of the network since the back-up traffic is done over a separate SAN in a LAN-free backup.

Many SANs have been built in a basic configuration with a Fibre Channel connection from multiple servers to one or two SAN-attached RAID arrays, and in some cases a tape library.

The Fiber ChannelSAN market today revolves around switch vendors such as Brocade, McData, Vixel and Ancor, and storage/server vendors such as EMC, StorageTek, Hewlett-Packard, Compaq, and IBM.

Both options, namely SANs and NAS, have their relative strengths and weaknesses. The primary advantages ofSANs include speed and reliability, centralization, and data protection. Conversely, the main strengths ofNAS are interoperability of products from different hardware and operating software vendors, resulting in the overall lower cost of ownership and simplicity.there are few limitations like the below mentioned ones.

The server can only access data on the devices, which are directly attached to it.
If something happens to the server, access to data will fail (because the storage device is part of the server and is attached to it using SCSI)
There is a limit in the number of storage devices the server can access. In case the server needs more storage space, there will be no more space that can be attached, as the SCSI bus can accommodate only a finite number of devices. 
Also the server using the SCSI storage has to be near the storage device(because parallel SCSI, which is the normal implementation in most computer's and servers, has some distance limitations. It can work up to 25 meters.)
SAN (Storage Area Network) and NAS(Network Attached Storage)

The main things that differentiate each of these technologies are mentioned below.
How a storage is connected to a system. In short how the connection is made between the accessing system and the storage component (directly attached or network attached)
Type of cabling used to connect. In short this is the type of cabling done to connect a system to the storage component (eg. Ethernet & Fiber channel)
How are input and output requests done. In short this is the protocol used to conduct input and output requests (eg. SCSI, NFS, CIFS etc)

Since NAS systems can store, manage and access content locally or remotely from all your devices – NAS is a secure personal cloud for your data and is the best solution for users who are looking for:
Affordable large storage capacity, My Cloud has no monthly fees 
Easy to set up and configure, uses standard Ethernet connection 
Remote access and streaming of all your content 
File sharing across multiple devices 
Backup multiple computers within your network automatically 
Multi-bay NAS drives provide hard-drive RAID redundancy to protect your data 
Set up user permissions, folder privileges and restrict access to documents

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