RAID birth
By the University of California at Berkeley (University of California-Berkeley) in 1988, he published the article: "A Case for Redundant Arrays of Inexpensive Disks". Article, talks about the term RAID, and defines five levels of RAID. Berkeley purpose is to reflect the prevailing fast performance CPU. CPU performance is about to grow 30 to 50 percent per year, while the hard magnetic machine can only grow about 7%. The team hopes to find a new technology, in the short term, to balance immediately improve performance computing power of the computer.
RAID: Redundant Arrays of Inexpensive (Independent ) Disks
multiple disks into one "array" to provide better performance, redundancy, or both to provide
RAID function
improve IO capacity
disk read-write parallel
improve the durability of
disk redundancy to achieve
RAID implementation mode
External Disk Array: adaptation capabilities provided by the expansion card
connected to the RAID formula: onboard RAID controller, prior to installation in the BIOS, OS configuration
software RAID: OS achieved by
RAID Level
Multiple disks are grouped together behave differently
RAID-0: is also known as a striped volume strip
Read, write performance
available space: 100%
no fault tolerance
Minimum Number of disks: two or more
RAID-1：
Read performance, write performance is slightly decreased
the space available: 1 / n
with redundant capability
minimum number of disks: two or more
RAID-4
increases a parity disk
RAID5:
RAID5 RAID4 is an upgraded version of the data and corresponding parity information is stored on each disk consisting of RAID5, and parity information, and data corresponding to each stored on a different disk.
Read, write performance
available space 1-1 / n
least three disks
RAID-6：
Reading and writing performance
of free space: 1-2 / n
fault tolerance: Maximum two disk damage
minimum number of disks: 4, 4+
RAID-10：
Reading and writing performance
of free space: N * min (S1, S2 , ...) / 2
fault tolerant: each up to a bad image only
the minimum number of disks: 4, 4+
RAID-01
multiple disks to achieve RAID0, RAID1 and then combined into a
RAID-50
Multiple disks to achieve RAID5, and then combined into a RAID0
JBOD：Just a Bunch Of Disks
Function: a plurality of disk space combined use of a large contiguous space
available space: sum (S1, S2, ... )
RAID7
can be understood as a stand-alone computer store, with its own operating system and management tools that can independently
run, in theory, the highest performing RAID mode
Common Level:
RAID-0, RAID-1, RAID-5, RAID-10, RAID-50, JBOD
