What is RAID and How It Works?


what is raid

As more and more sensitive data is being stored on the cloud or servers, data security and redundancy is becoming a sensitive issue nowadays.

In order to prevent data loss, there must be a reliable solution to ensure data availability in the event of hardware or software failure.

Hence in this article, let’s discuss RAID (Redundant Array of Independent Disks) – a powerful physical disk solution capable of ensuring the redundancy of your data.


What is RAID?

A RAID is a group of independent physical disks that save data and at the same time allow access of data at a high-performance rate.

RAID disk subsystem improves I/O performance and data availability on the server storage. Data availability is improved because several hard disks are accessed simultaneously.

RAID’s main function is to recover data loss caused by a physical disk failure by rebuilding missing data from the remaining physical disks that contain data.

RAID is not a backup solution. Therefore, it does not replace a good data backup solution for data retention and security.

Let’s have a look at different levels and types of RAID:


  • RAID 0
    Strip disk to provide high data throughput, especially for large files in an environment n that requires no data redundancy.
  • RAID 1
    Perform disk mirroring so that data written to one physical disk is simultaneously written to another physical disk.
  • RAID 5
    Uses disk striping and parity data across all physical disks (distributed parity) to provide high data throughput and data redundancy, especially for small random access.
  • RAID 6
    It is an extension of RAID 5 and uses an additional parity block. RAID 6 uses block-level striping with two parity blocks distributed across all member disks. RAID 6 provides protection against double disk failures and failures that occur while a single disk is rebuilding.
  • RAID 10
    RAID 10 or RAID 1+0 is a combination of RAID 0 and RAID 1. It uses disk striping across mirrored disks. It provides high data throughput and complete data redundancy. RAID 10 can support up to eight spans, and up to 32 physical disks per span.
  • RAID 50
    RAID 50 or RAID 5+0 is a combination of RAID 0 and RAID 5 where a RAID 0 array is striped across RAID 5 elements. RAID 50 requires at least six disks.
  • RAID 60
    RAID 60 or RAID 6+0 is a combination of RAID 0 and RAID 6 where a RAID 0 array is striped across RAID 6 elements. RAID 60 requires at least eight disks.


In Exabytes, most of our server plans are equipped with dual physical storage disks.

With the use of RAID 1, your storage data will be mirrored (or copied) to other disks simultaneously.

This helps to ensure when problems occur on one of the hardware disks, another disk which has the mirror image of the data can serve as a backup copy to recover your data.


The commonly used RAID for servers is RAID 10, which is a combination of RAID 0 (data striping) and RAID 1 (disk mirroring) to ensure data can be mirrored easily.

Data is striped across all mirrored drives. Since each drive is mirrored, no parity calculation is done.

As a result, no delay is encountered. In the RAID 10 strategy, data loss on multiple drives can be tolerated provided at least two drives of the same mirrored pair do not fail.

RAID 10 volumes provide high data throughput and complete data redundancy.