RAID explained

That term RAID stands for Redundant Array of Inexpensive Disks (also referred to as Redundant Array of Inexpensive Disks) and was first coined in the late 1980’s. RAID is a virtualization technique to reduce the possibility of data loss caused by hard disk hardware failure.

It works by replicating data across two or more physical hard drives linked together by a RAID Controller. The RAID controller can be either hardware based or software based.

Most types of RAID use an error reduction technique referred to as data ‘parity’ to offer fault tolerance where data is duplicated to reduce the impact of data loss through hardware failure.

RAID can be used for SATA, SAS and SSD Drives.

There are various types of RAID setups. Each type of RAID addresses a different goal in terms of the particular need to address a particular requirement such as:

  • Data Reliability – i.e. data is error free
  • Data Availability – i.e. data is available even in event of hardware failure
  • Data Performance – i.e. data access is fast whether for read and write operations
  • Data Capacity – i.e. amount of data stored is high

The most popular types of RAID are summarised as follows:


Data is ‘striped’ across at least 2 hard drives. RAID 0 offers higher performance but zero fault tolerance, i.e. 1 hard drive fails and data is lost on that drive.

Examples of use are where high performance is required for non critical data.


Data is ‘mirrored’ across minimum of 2 hard drives. This is fast, simple technology that offers basic fault tolerance.

RAID 1 is ideal for smaller businesses where cost is an issue (only 2 drives required) and data availability is critical.


RAID 5 required between 3 to 16 hard drives. Data is ‘striped’ with a parity block of the data stored on one of the drives. RAID 5 is fast and secure technology.

A good all round solution that balances efficiency, security and performance.


Belt and Braces version of RAID 5 with parity data stored on 2 drives instead of one. More fault tolerant than RAID 5 but comes with a performance overhead and restores are slow.

Raid 6 is suitable for situations where performance can be sacrificed at the expense of additional data availability.


RAID 10 offers advantages of RAID 0 and RAID 1. Data mirrored and striped across multiple drives. Fast storage and recovery but has a capacity overhead with minimum of 4 disks required.

Ideal choice for front line data where performance and availability are required at the expense of data capacity.

Which Type Of RAID does Pickaweb Use?

In our shared hosting and reseller hosting we use RAID 10 to offer fast speeds and increased uptime due to fast restore times in the event of hard drive failure.

For VPS and SSD VPS we use a cloud setup where data is stored on several disks on several physically different servers.

We hope you have found this tutorial useful on what RAID is.

Thanks for reading and leave your questions below to keep the conversation going.

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