Network Attached Storage

Network Attached Storage is basically a group of one or more hard disks contained in a single device and connected to a network to provide centralised backup for everyone on the network. A NAS device can also if properly configured provide fault tolerance for the data, depenmding on how it uses its logical disks.

A network attached storage device gets its fault tolerance by configuration of its logical disks into a RAID Configuration. RAID stands for either Redundant Array of Independant or Inexpensive Disks.

Even a networkattachedstorage device with only one physical hard disk can be configured with RAID, as a single hard disk can be divided into two or three logical drives.

RAID 0

RAID 0 doesn't offer any fault tolerance or data protection, all it achieves is that the data itself is written and thus read from two drives making the reading and writing faster.

RAID 1

This offers data protection as the data on one drive is mirrored onto a second, adding a somewhat small level of fault tolerance and data security.

RAID 5

This RAID uses three drives unlike the previous RAID levels which require two, data is written to all three disks, however a parity bit is also written to one of the three drives, containing the data previously written. Thus using this parity bit if one drive fails then it can either be swapped for another disk in the array or replaced and thus the data can be rebuilt.

RAID 4

RAID 4 as the names suggests uses four disks, however still three are used as data disks, the fourth being used for a deicated parity disk, thus instead of the parity data being distributed as in RAID 5 it has its own disk

RAID 6 or DP

RAID six is also called DP standing for duel parity, this is because there are 3 disks used for the data and two disks used for the parity, this makes RAID DP able to cope with two data disks going down as apart to RAID 5 and RAID 4 which can cope with only 1.

Centralised Storage :- Allows you to store data centrally thats easily accessible from any computer on the network

Data Security:- Having a network attached storage device allows you to protect your data using a RAID configuration, because data can either be mirrored or protected with parity bits or drives.

Play Multimedia from a centralised Location :- Instead of having films on one device and music on another fragmented across different devices, add a network attached storage device to a multimedia server and you can store all films and music centrally which can be accessed by many devices

Less Strain On Your Server:- Most servers are asked to do two or more jobs which include acting as a file server , why not give the job of file server to a nas device which will take strain of the main server and improve the network