Raid0 description: Maximum capacity guaranteed speed
Raid0 is also called stripe (striping) or striping (striping mode), it has the highest storage performance among all RAID levels< /p>
The principle of Raid0 to improve storage performance is to distribute continuous data to multiple disks for access. In this way, when the system has data read and write requests, multiple disks can be executed in parallel, and each disk reads and writes its own part of the data request. This parallel operation on data can make full use of the bandwidth of the bus and significantly improve the overall disk access performance.
To make raid0, at least one physical disk is required. Generally, different disks used for RAID should have the same size (which can give full play to the advantages of parallelism); and the data is stored on different disks, and then read and write. Concurrency can be achieved at the time, so raid0 has the best read and write performance, but it has no fault tolerance, that is, damage to any one disk will cause all data in the entire raid to be lost; a single disk used in production must be made into raid0, otherwise it cannot be used.
The disadvantage of Raid0 is that it does not have data redundancy. Therefore, once the user data is damaged, the damaged data will not be able to be restored. The characteristic of raid0 is that it makes users have higher performance requirements. Areas where data security doesn’t care much.
Production scenarios:
1. Multiple identical RS node servers under the load dredging cluster
2. The master node under the distributed file storage or CHUNK SERVER
3. Multiple slave servers replicated by Mysql master-slave
4. Related businesses with high performance requirements and low redundancy requirements.
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Points of interest |
Description |
| < p>Capacity |
is the combined capacity of four disks, and the raid level has the best storage performance. The principle is Continuous data is distributed to multiple disks for access |
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Performance |
Theoretically, the disk read and write speed is four times faster than a single disk. The more disks, the smaller the endorsement. |
Redundancy |
No redundancy, bad One disk, the entire raid can’t be used |
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occasions |
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Features |
Fast speed, no redundancy, no loss of capacity |
Raid1 : Maximum ability to ensure the availability of data
Description of Raid1:
Raid1 is also called mirror or mirroring (mirror), and its purpose is to maximize the availability and repairability of user data . The operation mode of Raid1 is to copy 100% of the data written by the user to one disk to another disk, thus realizing the storage of double data.
To make raid1, at least two fast disks are required (only two fast disks are supported?) The entire raid size is equal to the capacity of the smallest of the two disks (of course, it is best to use the same size disk ), the data is 50% redundant, and the data is written to two fast disks at the same time during storage to achieve complete data backup; but the write performance is relatively reduced, but the data can be read concurrently, which is equivalent to the read of two fast raid0 Acquisition efficiency (to be verified in practice)
Raid1 provides the best data security guarantee. Because 100% of the data is backed up, the disk space utilization is low and the storage cost is high. It is generally used for data security requirements. Fields such as server and database storage, or operating system disks.
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Points of interest |
Description |
| < p>Capacity |
50% loss of disk capacity |
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Performance |
Mirror cannot improve storage performance. Theoretically, the write performance is not much different from that of a single disk. |
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Redundant |
Among all raid levels, raid provides the highest data security guarantee, with a redundancy of 50% |
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Occasion |
Suitable for storing important data, such as server system partitions and databases with low performance requirements Storage |
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Features |
50% redundancy, half capacity loss |
Raid5: Moderate Plan
Radi5 It is a storage solution that takes into account storage performance, data security, and storage cost
Raid5 requires at least three physical disks, which can provide hot backup to recover from failures; it adopts parity, which is reliable The data is strong, and the data will be completely damaged only when two hard disks are damaged at the same time. When only one hard disk is damaged, the system will rebuild the data according to the stored parity bit and provide temporary services; at this time, if there is a hot spare disk, the system will still Automatically re-hot the spare disk to rebuild the data on the failed disk;
Raid5 will not back up the data, but will store the data and the corresponding parity information on each disk that composes the raid5, and the parity The check information and the corresponding data are stored on different disks. When a piece of disk data in raid5 is damaged, use the remaining data and the corresponding parity information to recover the damaged data.
Radi5 can be understood as a compromise between raid0 and raid1. Raid5 can provide data security for the system. The degree of single protection is lower than mirror and the disk space utilization rate is higher than mirror. Raid5 has a data reading speed similar to raid0, except that there is one more parity information for writing data. The speed is slightly slower than writing to a single disk. At the same time, because multiple data correspond to one parity information, the disk space utilization of raid5 is higher than that of raid1, and the storage cost is relatively low.
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Points of interest |
Description |
| < p>Capacity |
Loss the data capacity of a disk |
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Performance |
Raid5 has a reading speed similar to raid0. Just one more parity check information, the speed of writing data is slightly slower than a single disk writing operation |
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Redundancy |
A disk can be lost. The degree of data security of raid5 is lower than that of raid1 and the disk space utilization is lower than that of raid1. raid1 high |
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Occasion |
Raid5 can be understood as a compromise between raid0 and raid1. It is suitable for situations where performance and redundancy are required, but not very high. Both the master and slave libraries of Mysql can be used, and the storage can also be used. Ordinary servers can be used as raid5 in order to reduce maintenance costs and maintain certain redundancy and read-write performance. |
| < p>Features |
Capacity loss of one disk, write speed through parity check, raid0 and raid1 compromise scheme |
Raid10:
Raid1+0 means raid1 first and then radi0. As long as the two blocks on one side are not broken at the same time, it will be fine.
p>
Raid0+1 is to make raid0 first and then raid1. If one side breaks, the whole raid is broken.
Just like its name, raid1+0 is a combination of raid0 and raid1, also called For raid10
Taking raid0+1 composed of four disks as an example, its data storage method
Raid0+1 is a solution that takes both storage performance and data security into consideration. While providing the same data security guarantee as raid1, it also provides storage performance similar to raid0.
Since raid0+1 also provides data security through the 100% data backup function, the disk space utilization of raid0+1 is the same as that of raid1, and the storage cost is high
Raid10 and raid1 Differences
Raid10 and raid1 are logical combinations of disks in two different ways.
We all use four hard disks as raid to elaborate on the difference:
Raid10 first mirrors the two hard disks in the vertical direction, and then mirrors the two in the horizontal direction. Make strips. In short, raid10 is mirroring first and then striping. In this case, if only one of the hard disks is damaged, the impact on the raid group will not be very large. As long as one of the hard disks and its mirror disk are not damaged at the same time, the raid group will not crash.
< p>In comparison, radi10 has higher redundancy and higher security than raid01 system