C ++ arrayare becoming more and more common for small business users and those who have large amounts of data that must be stored and accessed on a regular basis. A RAID array is a group of two or more hard disk drives connected to a computer system that work together to store and retrieve data. There are several levels of RAID, which are various configurations noted as RAID 0, RAID 1 and so on.
RAID arrays were first conceptualized in 1978 by Norman Ouchi, an IBM computer scientist who wrote up a series of plans for a system which would eventually become RAID 5. In 1987 researchers at the University of Berkeley further developed the idea but were stumped by the fact that while RAID arrays offered much better storage capacity, they also tended to break down and crash much more often than single drive systems.
In 1988 David Patterson, Garth Gibson and Randy Katz wrote an article titled, "A Case for Redundant Arrays of Inexpensive Disks (RAID)". This was the first article to use the term RAID. The name stuck and is still used today.
At the present time there are a large number of RAID levels or configurations. Some of which such as RAID 1 and RAID 5 are very popular and others such as RAID 2, 3 or 4 are now obsolete. The various level of RAID arrays store data in different ways and allow for variations in the level of redundancy, protection from disk failure and speed of writing or accessing files from the array.
Here are some of the most important advantages of RAID arrays as they are used today:
RAID arrays can be more reliable.
RAID levels 1, 5, 6 and 0+1/10 provide protection against data loss due to the failure of one or more hard drives in the array. These RAID levels store data in more than one location on the array so that if one drive fails, the data can be recovered from other drives in the system. While the file is being restored, the computer system can still be used, although the performance tends to suffer a little in this state.
This application is very important to businesses that require access to their files to keep their enterprises running. Home users who store large amounts of data (for example large numbers of music or video files) can count on the increased reliability of a RAID data storage system.
RAID can increase performance.
RAID levels 0, 5 and 6 use a technique called striping which involves breaking up a block of data into small segments and storing those segments sequentially among the drives in the array. This allows you to access data more quickly and can make things such as music and video files operate much more quickly and smoothly.
Here are some of the most important disadvantages of RAID arrays as they are used today:
RAID cannot completely protect your data.
A RAID array only has one individual file system. As a result, while RAID arrays are good at protecting your data from physical disk failure, it's not as good at protecting your data from other problems such as file corruption, computer viruses, accidental deletion or natural disasters. The best way to protect your data is to back it up to a removable storage media such as an external hard drive and store the media off site.
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