A Redundant Array of Independent Disks (“RAID”) is a method in which you can use several disks in order to obtain performance and redundancy benefits. There are several layouts and they are denoted by numbers. Said numbers can be stacked for those same effects as well.
RAID 1 is also known as mirroring
With RAID 1, data is written to two drives identically and in the event, one drive fails in the RAID array, the second drive is identical in nature and provides you with a continuous workload. You need 2 drives for a RAID 1 array.
RAID 5 has parity & striping together
RAID 5 is considered a highly secure as well as high-performing RAID level. RAID 5 is one of the most popular raid types due to its performance & security of data. RAID 5 is considered highly efficient as it is not 1:1 like RAID 1. One of the downsides of RAID 5 is the reconstruction time of data in the event a drive fails.
RAID 6 has double parity with striping
RAID 6 is extremely similar to RAID 5, but it comes with double parity and can take a failure of two drives in the array. With RAID 5 you have the rebuild time which takes a lengthy amount of time but in RAID 6, that process is not lengthy because of the extra drive survivability.
RAID 10 is striping and mirroring (1+0)
RAID 10 is just RAID 1 + 0 combined, and as such, you are able to get the benefits of redundancy and speed but the amount of drives needed to do so is quite taxing. Rebuild times are extremely fast in the event of a drive failure due to the nature of RAID 1 + 0. The other RAID levels listed above can be cheaper and provide similar outcomes for most use cases, whereas RAID 10 is considered necessary where performance is the most important factor.