RAID (Redundant Array of Independent Disks) is a technology used to combine multiple physical disk drives into a single logical unit for the purposes of data redundancy, performance improvement, or both.
There are several types of RAID configurations.
RAID 0 (Striping)
Description: Data is split across multiple disks.
Advantages: Improved performance due to parallelism.
Disadvantages: No redundancy; if one disk fails, all data is lost.
Use Case: High-performance applications where data loss is not critical.
RAID 1 (Mirroring)
Description: Data is duplicated on two or more disks.
Advantages: High redundancy; if one disk fails, data is still available.
Disadvantages: Storage capacity is halved; higher cost.
Use Case: Critical data storage where reliability is important.
RAID 5 (Striping with Parity)
Description: Data and parity information are striped across three or more disks.
Advantages: Good balance of performance, redundancy, and storage efficiency.
Disadvantages: Write performance can be slower due to parity calculations; requires at least three disks.
Use Case: File and application servers where read speed and redundancy are important.
RAID 6 (Striping with Double Parity)
Description: Similar to RAID 5 but with an additional parity block.
Advantages: Can withstand two disk failures; higher redundancy.
Disadvantages: Requires at least four disks; more complex and slower write performance.
Use Case: Environments with large data sets and higher fault tolerance requirements.
RAID 10 (1+0)
Description: Combines RAID 1 and RAID 0; data is mirrored and then striped.
Advantages: High performance and redundancy.
Disadvantages: Requires at least four disks; storage capacity is halved.
Use Case: High-performance databases and applications requiring both speed and redundancy.
RAID 01 (0+1)
Description: Combines RAID 0 and RAID 1; data is striped and then mirrored.
Advantages: High performance and redundancy.
Disadvantages: Requires at least four disks; less efficient than RAID 10.
Use Case: Similar to RAID 10, but less common due to less optimal redundancy.
RAID 50 (5+0)
Description: Combines RAID 5 and RAID 0; data is striped across RAID 5 arrays.
Advantages: Improved performance and redundancy compared to RAID 5.
Disadvantages: Requires at least six disks; more complex setup.
Use Case: Large-scale storage systems where both speed and redundancy are important.
RAID 60 (6+0)
Description: Combines RAID 6 and RAID 0; data is striped across RAID 6 arrays.
Advantages: Can withstand multiple disk failures; high performance and redundancy.
Disadvantages: Requires at least eight disks; more complex setup.
Use Case: Enterprise environments with critical data requiring high fault tolerance and performance.
Non-Standard RAID Levels
There are several non-standard RAID types. Non-standard RAID levels like RAID 2, RAID 3 and RAID 4 are not commonly used today.
RAID 2
Description: Bit-level striping with Hamming code for error correction.
Use Case: Rarely used due to complexity and better alternatives available.
RAID 3
Description: Byte-level striping with dedicated parity disk.
Use Case: Rarely used; replaced by RAID 5.
RAID 4
Description: Block-level striping with dedicated parity disk.
Use Case: Less common; replaced by RAID 5 for better performance.
