I do understand RAID 1. You have two drives that are mirrored. So when one drive fails, you have the full set of data on the other drive.
But with RAID 5 you are able to lose a complete drive out of a set of 3 for example. You have full data redundancy without sacrificing half of your capacity. How does this work?
In: 5
The first 2 drives store half the data each.
The third drive stores the *difference* between the data on the first drive and the data on the second drive.
This sounds complicated on the surface, how could you describe the “difference” between an operating system file and a video for example?
But remember, at the bit level, data is just 1s and 0s. If you have a 1 on the first drive, you only need one tiny piece of information to determine what was on the second drive: was it the same (that means the second drive contained a 1) or was it different (that means the second drive contained a 0)?
Latest Answers