Overview
Redundant Array of Independent Disks (RAID) is a technology that combines multiple physical disks into one or more logical units for the purposes of data redundancy and performance improvement.
![](https://support.huaweicloud.com/eu/bestpractice-evs/public_sys-resources/note_3.0-en-us.png)
In this document, Elastic Volume Service (EVS) disks instead of physical disks are used to create RAID arrays. The working principles are the same.
- Resource planning: Resource Planning
- Resource creation: Creating an ECS and Creating and Attaching EVS Disks
Introduction to Common RAID Arrays
RAID Level |
Description |
Read/Write Performance |
Security |
Disk Usage |
Min. Number of Disks Required |
---|---|---|---|---|---|
RAID 0 |
RAID 0 stores data on multiple disks, implementing parallel read/write and providing the fastest read/write speed. |
Parallel read/write from multiple disks achieves high performance. |
Worst No redundancy capability. If one disk is damaged, the data of the entire RAID array is unavailable. |
100% |
2 |
RAID 1 |
RAID 1 implements data redundancy based on data mirroring. Half of the disk capacity in the RAID array is used, and the other half is used for mirroring to provide data backup. |
Read performance: Same as a single disk Write performance: Data needs to be written into two disks. The write performance is lower than that of a single disk. |
Highest Provides full backup of disk data. If a disk in the RAID array fails, the system automatically uses the data on the mirror disk. |
50% |
2 |
RAID 01 |
RAID 01 combines RAID 0 and RAID 1, in which half disks are first grouped into RAID 0 stripes and then used together with the other half to set up a RAID 1 array. |
Read performance: Same as RAID 0 Write performance: Same as RAID 1 |
The security of RAID 01 is lower than that of RAID 10. |
50% |
4 |
RAID 10 |
RAID 10 combines RAID 1 and RAID 0, in which half disks are first set up as a RAID 1 array and then used together with the other half to create RAID 0 stripes. |
Read performance: Same as RAID 0 Write performance: Same as RAID 1 |
The security performance of RAID 10 is the same as that of RAID 1. |
50% |
4 |
RAID 5 |
RAID 5 does not specify a dedicated parity disk and consists of block-level striping with parity information distributed among the disks. |
Read performance: Same as RAID 0 Write performance: Because parity data needs to be written into disks, the write performance is lower than that of a single disk. |
The security of RAID 5 is lower than that of RAID 10. |
66.7% |
3 |
Feedback
Was this page helpful?
Provide feedbackThank you very much for your feedback. We will continue working to improve the documentation.