RAID celebrates its 30th aniversary

ExtremeTech reminds us that redundant array of independent disks (RAID) technology is now 30 years old! The site reports the entire idea behind RAID was to develop a more affordable storage system that could math the performance of IBM's standard mainframe disks. While RAID striping has its disadvantages, like if one disk fails all data is lost, it did enable a very welcome performance boost in the pre-SSD era. Alternatively, RAID also offers other modes like mirroring, which ensures all data is written simultaneously on two or more disks.

Patterson, Gibson, and Katz defined a variety of RAID levels to suit various tasks and strategies. Today, RAID 2 and RAID 3 are rarely used, while motherboards typically offer software RAID support for RAID 0, RAID 1, and RAID 10. Some boards and controllers also support RAID 5. RAID 0 is data-striping only–you get the advantage of writing data to two disks at once (boosting performance), but you increase the chance of catastrophically losing data. If each drive has a 1 percent chance of failure (just as an example), then the chances of losing a drive and all of your data is 4 percent, since any failure will kill the array. RAID 1 is mirroring–all of the data on Drive 0 is simultaneously written to Drive 1.