Over the last couple of months I’ve been using a hack to allow software RAID 5 on Windows XP. This hack has worked great for the few months I’ve used it, but I have found a two key features missing from Windows XP’s implementation of software RAID. The first missing feature is the ability to add a hard drive to an existing RAID 5 array. The second missing feature is the ability to make different RAID setups appear as one drive. For example, let’s say I have three 500gb hard drives in a RAID 5 and two 250gb hard drives in a RAID 1. I would like the ability to make these two different arrays function as one big drive. After a little bit of research, I’ve found that Linux is the solution to my problem. Also, I’ve found that Linux has support for software RAID 6 and RAID 10, a nice bonus if users are looking for increased fault tolerance or increased speed. Although RAID on Linux was a little bit tough to set up, because I’m not used to Linux and because Linux developers aren’t the best with GUI’s, I eventually worked it out.

Step #1 Pick the desired RAID and get the needed hardware.

The first step is to decide on the type of RAID. Go to my article on simple RAID level explanations to find out the differences between the different levels or RAID. Once the desired RAID level is picked, it’s time to move onto hardware. The amount and size of hard drives needed to achieve the desired setup needs to be figured out. When deciding how many hard drives will be needed keep in mind that one hard drive of 10gb or more will be needed to accommodate the OS. Also, linux should run on almost any motherboard, CPU and Video Card combination.

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What’s the difference between RAID 0 and 1? Is RAID 5 the best? If you find yourself asking these questions here’s a quick summary of the standard RAID levels. For the sake of simplicity, I’m only going to cover JBOD, RAID 0, RAID 1, RAID 5 and RAID 6.

JBOD (Just a Bunch of Disks) or Spanned Array

JBOD isn’t an official RAID setup, but most RAID setups offer it as an option. A JBOD array basically takes a bunch of disks and turns them into one big partition. JBOD offers no redundancy and with some RAID setups, the failure of one disk in the array will cause the whole JBOD array to fail. Unlike RAID 0, a JBOD array reads and writes at the same speed as a normal disk.

RAID 0 or Striped RAID

The first level of RAID is RAID 0, commonly referred to as striped RAID. This level of RAID is only for users looking for speed. RAID 0 requires at least two drives. RAID 0 is very dangerous for users looking for reliability. If one disk in the RAID array dies the whole array is trashed. Generally the more disks in the array the faster read and write times will be, but the greater the chance of the array failing. The size of a RAID 0 array is the size of all the drives in the array combined.

RAID 1 or Mirrored RAID

The second level is RAID 1, also know as mirrored RAID. This level of RAID will increase reliability, but requires two drives of the same size. RAID 1 makes an exact copy of a hard drive therefore using 50% of the total storage for redundancy. For example, if a user has two 500GB hard drives making their array 1TB they will have 500GB of actual storage. In most RAID setups, RAID 1 will increase the the read speed but will slightly decrease the write speed.
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