RAID disk array 0, 1, 5, 10

RAID0: ( also known as stripe or striping--sub-strips )

(Bottom line: RAID0 uses multiple disks in series to form a large disk with a sum of several volumes.) Advantages: Large capacity, fast speed. Cons: Data insecurity)

That is, data stripping is a sub-strip technology. RAID 0 can connect multiple hard drives into a larger drive group, which can improve disk performance and throughput. RAID 0 has no redundancy or bug fixes, is low cost, requires at least two disks, and is generally only used if the data security requirements are not high.

In theory, the parallel operation of the three drives increases the disk read and write speed by 3 times times over the same time. However, due to the influence of bus bandwidth and other factors, the actual increase rate will certainly be lower than the theoretical value, but, the large amount of data parallel transmission and serial transmission comparison, the speed-up effect is obviously undoubtedly.
The disadvantage of RAID 0 is that data redundancy is not provided, so corrupted data cannot be recovered once the user data is corrupted.
RAID 0 has features that make it particularly suitable for areas where performance requirements are high, while data security does not care much about the domain, shaped workstations, etc. For individual users, RAID 0 is also an excellent choice for improving hard disk storage performance.

RAID1: ( also known as mirror or mirroring--mirror )

(In a word: RAID1, half of the data is stored and the other half is backed up.) Advantages: Data storage security; Cons: Waste too much disk, only 50% utilization)

RAID 1 is called disk mirroring: The data of one disk is mirrored on another disk, and the reliability and repairable of the system can be guaranteed without compromising the performance, it has high data redundancy, but the disk utilization is 50%, so the cost is the highest, and it is used in the case of saving critical important data. RAID 1 is done by automatically copying the data that the user writes to the drive to a different hard disk.

RAID 1 has the following features :
(1), RAID 1 each disk has a corresponding mirror disk, at any time the data are synchronized mirroring, the system can be from a set of mirrors on any disk to read data.
(2), the disk can use space only half the total disk capacity, the system cost is high.
(3), as long as there is at least one disk in any pair of mirrors in the system can be used, and even in half the number of hard disk problems when the system can operate normally.
(4), a hard disk failure of the RAID system is no longer reliable, should promptly replace the damaged hard disk, or the remaining mirror disk also has problems, then the entire system will crash.
(5), after the replacement of the original data will take a long time to synchronize the image, the external access to the data will not be affected, but the performance of the entire system has declined.
(6), RAID 1 disk controller load is quite large, with multiple disk controllers can improve the security and availability of data.

When the data is read, the system first reads the data from the RAID1 source disk, if the reading data is successful, the system does not control the data on the backup disk, if the reading of the source disk data fails, the system will automatically read the data on the backup disk without causing the user to interrupt the work task.

RAID5: ( can be understood as a compromise between RAID 0 and RAID 1, using "parity information" as a way to recover data )

(Bottom line: RAID5 is a combination of RAID0 and RAID1, disk utilization, faster transfer rate, data backup, separate disk to back up parity information, to recover data)

In the figure, the AP is the parity information for A1,A2 and A3, and so on. As can be seen from the figure, RAID 5 does not back up the stored data, but instead stores the data and the corresponding parity information on each disk that makes up the RAID5, and the parity information and the corresponding data are stored on separate disks. When one of the RAID5 disk data is damaged, the remaining data and the corresponding parity information are used to recover the corrupted data.

RAID10: (known as the Mirror array strip)

(In a word: Total equals raid0 and raid1 function Accumulation ranid10 = RAID1 + RAID0, disadvantage is that disk utilization is less than or equal to 50%)

Like RAID0, data is pumped across the disk; like RAID1, each disk has a mirror disk, so another way to say RAID 10 is raid 0+1. The RAID10 provides 100% data redundancy to support larger volume sizes, but the price is also relatively high. RAID10 provides the best performance for most applications that require only redundancy, regardless of price. With RAID10, you get better reliability, because even if two physical drives fail (one in each array), the data can still be protected. RAID10 requires 4 + 2*n disk drives (N >=0), and can only use half (or smaller, if the disk size is different) disk usage, such as 4 250G hard disk using RAID10 array, the actual capacity is 500G.

Summarize:

type	Read and write performance	security	Disk Utilization	cost	Application Aspects
RAID0	Best (increased by parallelism)	worst (no security guaranteed)	Highest (100%)	min	personal User
RAID1	Read and single disk no distinction, write to write both sides	highest (100% backup for data)	Poor (50%)	highest	is suitable for storing important data such as server and database storage areas.
RAID5	read: Raid 5=raid 0 (similar data read speed)   Write: RAID 5< write to a single disk (more than one parity letter	raid 5<raid 1	raid 5>raid 1	raid 5<raid 1	is a storage performance, data security, and Storage solutions with a cost-saving solution.
RAID10	read: raid10=raid0   Write: raid10=raid1	raid10=raid1	raid10=raid1 (50%)	raid10=raid1	aggregates the benefits of RAID0,RAID1, but because of the use of mirroring instead of "parity information" like RAID5, disk utilization is a Sample is 50%

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RAID disk array 0, 1, 5, 10