RAID 0, RAID 1, RAID 10 - Things you need to know

In this post, we are going to tell you all you need to know about Raid 0, Raid 1, and Raid 10 in a more comprehensible way. You have probably read about RAID somewhere, but do you know what it really mean? It stands for redundant array of inexpensive disks and it means using multiple drives or disks to achieve better performance and/or better reliability.

Raid 0 is all about speed. It contributes nothing to reliability except actually it makes it worse. Therefore, it involves taking two drives or more actually striping all the data across all the drives. This means you get to keep all of your capacity and you get to have in theory two drives, double the read-and-write performance but in the event that one of the drives undergoes a hardware failure, you will lose all the data that was stored on both of the drives. This configuration is only ideal if you are going to be doing very frequent backups or if you are going for the most extreme performance possible such as running multiple SSDs.

Raid1 is all about reliability. You get the capacity of one of your drives and you get the performance of one of your drives, but you get the redundancy of two drives. This means if one of these two drives I have here fails outright, all the data will still be there.

There is no performance overhead for running Raid 1. You are still going to get the full performance of the drives but the more drives you add to a Raid 1, you are always only going to get half the capacity that you would otherwise have.

The advantage of Raid 1 is it is extremely safe, so I would trust most important documents to a Raid 1 array.

Raid 10 combines what is good about raid 0 and what is good about Raid1 into the same thing. Therefore, you are taking four drives, striping these two, and striping the other two, and then you are mirroring the first pair against the second pair. Therefore, what that means is you get about double the performance of an individual drive and you get double the capacity of an individual drive. However, you could lose up to two drives in a RAID 10 array without losing any data. This is great where performance is needed and space is needed. However, you do not necessarily want to invest on an expensive RAID card solution like this one.

There are types of Raid that we have not covered in this post but we will make another one so there will be an annotation. However, those are generally reserved for professional applications.

Finally yet importantly, RAID is not a substitution for backing up. Redundancy is not the same thing as a backup, even if you are running a RAID, you are still susceptible to things like viruses, or accidental deletion, or other human errors. So, make sure that you are doing regular backups.