Understanding RAID 0, RAID 1, RAID 10, and RAID 5: Features, Pros, Cons, and Usage Recommendations

Server storage is driven by speed and reliability requirements, giving rise to several disk‑array schemes such as RAID 0, RAID 1, RAID 10, and RAID 5.

What is RAID 0?

RAID 0 combines two or more physical disks into a single logical drive, but the total capacity equals the size of the smallest disk multiplied by the number of disks. For example, two 250 GB disks in RAID 0 yield 500 GB.

Advantages of RAID 0

Treats the entire array as a single entity, improving read/write speed.

Maximizes disk space utilization.

Requires at least two disks.

Disadvantages of RAID 0

A single disk failure causes loss of all data in the array.

Data recovery is complex because data is striped across all disks.

Total capacity is limited by the smallest disk.

Usage Recommendations

Ensure all disks have the same size.

Suitable for scenarios where data safety is not critical.

What is RAID 1?

RAID 1 mirrors data across at least two disks, providing high reliability; if one drive fails, the other continues to operate. It offers high read performance, but write speed is slower because data must be written to all mirrors.

Advantages of RAID 1

Strong data redundancy and fault tolerance.

High read performance.

Easy to maintain and recover.

Disadvantages of RAID 1

Higher cost due to the need for at least two disks.

Write performance is lower because data is written to multiple disks.

Usage Recommendations

Ideal for read‑intensive applications.

Recommended where data reliability is a high priority.

What is RAID 10?

RAID 10 (or RAID 1+0) combines the striping of RAID 0 with the mirroring of RAID 1, delivering both performance and redundancy. It can tolerate the loss of any single drive (or even a second drive in some cases) without data loss, but requires at least four disks.

Advantages of RAID 10

Strong data redundancy and fault tolerance.

Fast recovery speed.

High performance.

Disadvantages of RAID 10

Higher cost due to the need for more disks.

Lower disk utilization efficiency.

Usage Recommendations

Suitable for scenarios demanding both high performance and high reliability.

Ideal when rapid data recovery is required.

What is RAID 5?

RAID 5 requires at least three disks and distributes data in stripes across them while storing parity information on each disk. This parity provides fault tolerance: if a single disk fails, the data can be reconstructed from the remaining disks.

RAID 5 offers zero downtime and very high read speeds, though write performance is slightly slower due to parity calculations. It is cost‑effective for environments with a limited number of drives, making it a popular choice for database servers and read‑oriented applications.

The configuration sacrifices about 33 % of total capacity for parity when using three disks; with four disks the overhead drops to 25 %, and it can scale up to 16 disks.

Usage Recommendations

Best for file and application servers where a balance of performance, redundancy, and cost is needed.

Especially suitable for read‑heavy database workloads.