RAID 10, sometimes known as RAID 1+0, combines the mirroring of RAID 1 with the striping of RAID 0, offering a great solution for high-performance environments that need that added security.
We’ve recently written an article on how RAID 0 and RAID 1 differ, and what the advantages and disadvantages of both RAID levels are – but it’s worth going over the basics here. RAID 0, also known as ‘striping’, turns two or more hard disk drives into one single drive with a higher capacity and greater speeds. A RAID 0 array is essentially a sum of its parts; an array with two 3TB HDDs gives you a storage unit with 6TB of space, and double the number of read/write heads. RAID 0 is perhaps the purest form of RAID. The major disadvantage of RAID 0 is that because your data is striped across both or all disks in the array, if one drive fails, you lose your data, and it must be repaired before the data is accessible again. The more drives in a RAID 0 array, the greater the chance of failure, which is why RAID 0 arrays are generally limited to two hard drives.
RAID 1, or ‘mirroring’, offers redundancy, due to data being mirrored across all drives in the array. In addition, read speeds are faster due to all read/write heads being in operation, but write speeds are slower due to the data being written across all drives. The major downside of a RAID 1 array is that it only has the storage capacity of one drive, since each drive contains an identical copy of the data.
RAID 10/1+0 combines the mirroring of RAID 1 with the striping of RAID 0, and is best suited for environments which require high performance and security. RAID 10 requires a minimum of four hard disk drives, and data is striped across mirrored pairs. RAID 10 is fast, since data can be read and written to different drives simultaneously. Additionally, as long as one disk in each mirrored pair is operational, no data will be lost. There are two main disadvantages of RAID 10, however. Firstly, because data is mirrored, only 50% of the total storage capacity is usable. Secondly, if two drives in the same mirrored pair fail, then data will be lost. RAID 10 is also more expensive than other RAID levels, like RAID 0, 1 and 5. However, what RAID 10 does offer is improved performance, a high read/write rate, and data redundancy. It offers the combined benefits of RAID 1 and RAID 0 – with some of the pitfalls, too.
