An Article on RAID Arrays

[TheDitchy 5]

Hey Guys,

I though I'd write an article on RAID Arrays for any of you that are interested. Let me know if you guys think I should do some more of these articles.

 

A RAID Array is a ?Redundant Array of Independent Disks? which combines multiple Hard Disks to create data redundancy, performance improvement, or both. I?ll only be covering the main and mostly used RAID levels as they are the most popular. I?m also not covering all different types of RAID as they get very confusing and most just improve on another.

 

 

A RAID 0 is where data is written across multiple drive. For example, if you had an image of your family, half of that image would be stored on one drive the rest of the image on another (Or in the case of more than 2 drives, the file will be split equally across all drives.) Because each drive is being used to store the image, the read and write speeds of a RAID 0 is a lot higher because the data is written across the drives and doesn?t have to wait until all of it stored by one drive. The downside to RAID 0 though is that if you have 2 drives in a RAID 0 and one of them fails, then half of your data is lost as the data is stored equally across the drives. If you are combining multiple drives with different sizes of storage then the RAID storage would only be as high as the smallest sized drive in the RAID array. RAID Arrays above level 0 provide protection against loss of drives and data.

 

RAID 1 is where the data written to one drive and also written to another. So your picture of your family is written fully to both drives in your RAID Array. This is great because if one drive fails then you have a backup that is a clone of your other drive. The downside to RAID 1 is that you will not have more storage as the other drive acts as a clone which could make your RAID array expensive if you have high capacity drives. The Storage space on a RAID 1 is also only as high as the lowest sized drive.

 

RAID 10 is Simple. It is the combination of RAID 0 and RAID 1. For example, if you had 10 drives, then 5 of this drives would be group 1 and the other 5 would be group 2. Group 1 is connected together via RAID 0 for fast file read and writes because the data is being split amongst them. The other 5 act as RAID 1s for the other drives. So they become backups of Group 1. This allows for data integrity and backups as well as faster read and write speeds. The downside to RAID 10 is that it is very expensive and you need at least a minimum of 4 drives. if each drive is ?50 and you need 4 for a small RAID 10 then that is ?200 so you can see how easily the cost rises with a RAID 10. RAID 10 is also the most efficient and safest way to back up data. (Unless you want a RAID 60 but that is just silly.)

 

An example of a RAID 10 is the server this website is using. They used a RAID 10 to store all the data which gave them fast speeds and safety knowing that there was an active backup being constantly made. Unfortunately, 1 drive died which meant the backup of that drive should have taken over and it should have been as easy as replacing the broken drive with a new one and rebuilding the array. But as luck would have it, the backup of that drive failed at the same time too meaning a sizeable chunk of data was lost. Now any half decent company will have at least 3 backups of the data but the reason the site was down so long was because of the data loss and they had to rebuild all of the data in the RAID array.

 

 

Also you are welcome to ask any questions about RAID and I?ll happily help. If you would prefer to learn more about RAID then I recommend the Wikipedia page on it: https://en.wikipedia.org/wiki/RAID or if you are more of a visual learner, here are some links to a YouTube video which may help you:

[Mathew Steel 151]

Interesting read. I have a lot of interest in learning things like this, thanks for sharing it! :)