The same is true when you consider data protection instead of disk performance.įor those reasons, RAID arrays are likely to be a sensible solution to storage problems more often in companies which have SDD storage infrastructure in place. In an HDD storage environment, situations where single disk performance is inadequate for a specific workload will occur more frequently than in an SSD storage environment, simply because HDDs offer lower performance. This is important, because a RAID array can help you achieve better performance or better protection against disk failure, or both. When considering the relative attractiveness of HDD RAID v SSD RAID setups, two facts are key: These different RAID configurations offer different combinations of performance gains, data protection, and storage efficiency. In fact there are many other RAID configurations which use different numbers of disks, and techniques such as RAID stripe storage (splitting data between different disks) and storing parity bits.
(SSDs are much more energy efficient than HDDs, so this point is less. Users consume about twice the power of a single drive system.Users can only use half of the total storage capacity of the two drives (a storage efficiency of 50%).The main drawbacks to an SSD RAID 1 array are: RAID 1 also provides a degree of performance enhancement because any read request can be handled by either drive in the SSD RAID array. Using an SSD RAID in a RAID 1 configuration, if one drive fails then no data will be lost, because the data it stores is also mirrored on the other drive in the SSD RAID array. This is due to the corruption of individual bits stored in the NAND cells through interference between cells or even complete cell failure due to heavy usage. But even though complete disk failures are rare, data stored on an SSD can still be lost. SSDs tend to be highly reliable as they have no moving parts and because they generate less heat than HDDs so do not suffer wear from thermal expansion. Here’s how RAID and SSD are used together to prevent failure/losing data: RAID performance benchmarks increase markedly when there are multiple SSDs crunching data. By using different RAID levels it can also be used to provide a combination of the two, in varying proportions.
The bottom line is this: RAID can be used to increase disk performance, or to provide protection from data loss in the event that one (or sometimes more than one) disk in the array fails completely or partially. The simplest array configuration that offers data protection is one that provides mirroring: data stored on one drive is copied to the other so that each is a mirror image of the other. The term RAID comes from the phrase “Redundant Array of Inexpensive Disks,” and perhaps the most important word in that phrase is “Inexpensive.” That’s because RAID was coined in 1987 by computer scientists who wanted to demonstrate that standard, inexpensive disks configured in a suitable RAID array could offer performance that was superior to expensive high performance disks that were available at the time.īut the use of an array of disks that presents itself to a computer system as a single storage device had been commonplace before the term was coined, mostly for data protection purposes. Clearly, flash storage memory has its challengesįor that reason, SSD RAID can also be extremely useful when used with SSDs in applications where data protection is particularly important. Although SSDs tend to be more reliable than HDDs because they have no moving parts, they are still prone to failure. Some SSD RAID configurations can also be used to protect data in the event of a disk failure. HDD debate, the SSD RAID clearly shines in performance. Plus, using SSD RAID arrays can lead to further performance gains, so rather than being an alternative to RAID, SSDs should really be seen as a complement to RAID. But a single solid state drive (SSD) RAID array can offer performance which is comparable to many HDD RAID arrays, and is therefore often seen as an alternative to an SSD RAID array.
RAID arrays have been used for more than 40 years to increase the performance of hard disk drive (HDD) storage systems.