Understanding RAID – Part 1

Working in the IT industry comes with so many different problems that it borders on the ridiculous. I decided to start writing about something that may actually be of interest to small businesses when deciding to upgrade their servers or implement new servers to an existing network. There are many things to consider when this…

Working in the IT industry comes with so many different problems that it borders on the ridiculous. I decided to start writing about something that may actually be of interest to small businesses when deciding to upgrade their servers or implement new servers to an existing network. There are many things to consider when this happens but I thought that explaining something that most people would not know or understand seemed as good a starting point as any. This is also quite important to your business for several reasons which I will illustrate further into the article.

RAID Configurations

Doing server installs got me thinking about RAID configurations and the different setups and reasons behind using each different configuration. From a business stand point most companies just trust their IT technicians to use the best qualified configuration for their business, without actually understanding the reasoning behind the RAID setup. Sometimes we are given system specs from our clients which include the required RAID setup although having done some of these installs I am still not convinced that they fully understand why the setup has been used.

First off what does RAID stand for? Redundant Array of Inexpensive (or Independent) Disks. This is basically a system of using multiple drives to act as one and as such you get several benefits out of them, such as redundancy in case a drive fails or speed for reading files faster and in some configurations you get both. However you do lose disk space for eg if you use 2 x 100GB drives in a RAID configuration, you will essentially have only 100GB of storage space.

And This Means ….

Understanding the use of RAID setups is helpful for when your business needs to upgrade your servers or just change the current setup for something that suits your business better. Budget and downtime constraints are also things that should be considered before making any changes to your currently installed configuration. It's also useful to note that some setups are more effective while utilizing multiple RAID configurations on the same server.

Apples and Oranges or Bananas and Muffins

When data is written to multiple disks it is either striped or mirrored. Some RAID configurations use both methods and some use only one or the other. Further into this article I will explain which configuration uses which method.

So what is the difference between striped and mirrored? Basically striped RAID is used for speed as part of the file is written across two or more drives, however if one of the drives fails you have lost all your data as there is no redundancy with this method.

Mirrored RAID is slower than striped but has the added advantage of redundancy, your data is written twice, once to each drive so if one drive fails you have all your data safely on the second drive. This method is very important if you have sensitive or important data that requires backup. Please note that using a mirrored RAID configuration is no excuse to not have a reliable regular backup system in place!

Next week I will go over the different types of RAID configurations and explain their differences as well as their pros and cons.