While traditional RAID utilised hard disk drives (HDDs) as the primary storage media, in recent years vendors have begun to extend the concept to solid-state drives (SSDs)
RAID, or redundant array of independent disks, far outdates the widespread use of flash-based SSDs that are slowly taking over from traditional mechanical HDDs. With the rise of the SSD, the question now is whether to adopt this comparatively new technology into RAID systems.
SSDs are faster, more durable and reliable, more power and energy efficient, have smaller form factors, and are lighter and make no noise; all benefits over larger, slower, noisier HDDs. One way to make HDDs faster is to combine them into a RAID 0 configuration, also known as striping. With RAID 0, data is striped across both disks in the array. However, if one of the drives fails, the data will be lost. RAID 0 also provides double the storage capacity. However, when it comes to speed, an SSD will win out against a RAID 0 setup any day; even the fastest HDDs in the world can’t compete with an average SSD.
When considering SSD RAID, you need to take into account performance, reliability, and price. In terms of performance, an SSD RAID configuration will always beat an HDD RAID setup – there really is no competition in terms of raw performance. What you have to consider is if it’s worth it in terms of reliability and price. While the cost of NAND flash chips used to store data in SSDs has gone down considerably in recent years, the cost-per-gigabyte is still way higher compared to HDDs. Additionally, the storage capacity of HDDs has soared in recent years, and SSDs simply can’t compare.
In terms of reliability, you need to factor in SSD endurance. Essentially, SSDs wear out when they’ve had data written to them too much, although modern SSDs are far more durable. Another thing to consider is that SSD RAID enables faster rebuilds in parity-based RAID setups.