Choosing a RAID level is a balancing act between cost, reliability, capacity, and performance. For many users, enhanced performance is the most important element.
RAID combines multiple disks into a single unit, and can be set to a number of different levels depending on what the user wishes to achieve. Depending on your needs, the RAID can be configured to offer increased speed/performance, storage capacity, reliability, or often a combination of all three. RAID stands for Redundant Array of Independent Disks, and the controller combines the disks in the array into a single storage unit.
RAID 0 is essentially the most basic RAID level. Also known as disk striping, the data is striped across two or more drives, offering increased storage space. Because there are multiple sets of heads working together, read/write speeds are faster. However, RAID 0 provides no redundancy; because data is striped across all the drives in array, if one drive fails, the result is data loss. For every drive that is added to a RAID 0 array, the user will get increased speed and capacity, but also an increased chance of failure. For this reason, it is typically uncommon to see RAID 0 arrays with more than two drives.
RAID 1 is known as disk mirroring, and here, the controller replicates the data across all drives in the array, so if one drive fails, there are still copies of the data. One major downside, however, is that you only have the storage capacity of a single drive, since each of the other drives contains a copy. In terms of performance, read speeds are faster due to multiple heads being in use. However, write speeds are slower, as data needs to be written to all drives in the array. RAID 1 is typically a good solution for home users who don’t require a lot of storage space, but would like some data redundancy and improved read speeds.
RAID 10 – also known as RAID 1+0 – combines the mirroring of RAID 0 with the striping of RAID 1, offering high performance as well as some redundancy to protect against data loss. Requiring a minimum of four hard drives, data is striped across mirrored pairs, and as long as one disk in each pair is operational, the data is still accessible. The striping element offers increased read/write speed, too. RAID 10 essentially offers the best of both worlds – the performance of RAID 0 and the redundancy of RAID 1. This makes it an ideal RAID solution for those who want a storage unit that performs well, but want their data protected.
