Which RAID Option is right for you? RAID Levels Explained

July 20, 2015

There are many RAID options available, and it can be hard to know which option is best for you. By following this guide, you can determine which of the RAID options is best for your hosting and what drive sizes to use.

In general, with all forms of RAID you want identical drives, so different drive sizes or other specs can cause problems such as wasted capacity or slower read/write speeds.

RAID 0

The first of the RAID options is RAID 0. With RAID 0, each disk in the set behaves as a single disk through a process called striping. This striping process writes data quickly by splitting it in a roughly equal amount across each drive at the same time. That is the main advantage of RAID 0: speed. However, if one drive crashes, this breaks the array and usually causes data loss.

RAID 1

The next RAID option is RAID 1. RAID 1 writes data identically to two or more drives, a process called data mirroring. This can improve data access speed, but it can slow down data write speed. A best practice is to make sure the drive sizes are identical for all drives involved. If one drive crashes, this array can continue to function because the drives duplicate the data.

RAID 5

The next common RAID option is RAID 5, generally the most common choice for business servers or enterprise NAS devices. It requires at least 3 disks and uses a parity block on each disk. This means your entire array will not fail even if one disk does, as long as you replace it before another one fails.

RAID 6

Next is RAID 6, which is almost the same as RAID 5 but uses an extra parity block. This means two disks can crash and the system will still function correctly.

RAID 10

The last common RAID option is RAID 10 (or 1+0). RAID 10 requires at least 4 disks and combines the striping of RAID 0 with the mirroring of RAID 1. It provides the best read and write performance, but is the most costly.