Why HighPoint SSD7500, SSD7000 Series NVMe RAID controller do not support RAID 5 and 6?

This knowledge base (KB) applies to the following NVMe RAID AICs.

Table 1: Support NVMe RAID AICs

Support NVMe RAID AICs

SSD7101A-1 SSD7104 SSD7105 SSD7204 SSD7140A SSD7540 SSD7749M SSD7749M2 SSD7749E SSD7505 SSD7202 SSD7502 SSD7120 SSD7180 SSD7184 SSD7580B SSD7580C

For many NVMe-based storage applications, the security-performance tradeoff required for RAID 5 & 6 support is less than ideal. NVMe media is significantly more reliable than platter-based storage (conventional hard disk drives), which redundant RAID technology was developed for. And it should be noted; TBW status and SMART data enable administrators to predict, with great accuracy, when an NVMe SSD should be replaced. NVMe media’s inherit reliability is why many are comfortable with RAID 0 being designated as the “default” configuration for the majority of NVMe-based storage solutions.

In general, RAID 5 & 6 is not recommended for today’s commercially available NVMe SSD’s. This applies equally to hardware, hardware-assisted and software-based RAID solutions.

RAID 5 & 6 arrays are able to reconstruct data after hardware failure through the use of parity.

Parity is spread across each member of the RAID array, and must be periodically synchronized (rebuilt and rewritten) in order to ensure the integrity of data. Maintaining parity for RAID 5 & 6 configurations significantly impacts the lifespan of NVMe media, which have finite write endurance. This endurance rating, or lifespan, is most commonly expressed as TBW (Terabytes Written) and DWPD (Drive Writes Per Day).

While it is true that RAID 5 & 6 arrays provide an additional layer of security; it comes with a cost. Even if one puts asides concerns about TBW, it is impossible to ignore the fact that maintaining parity requires dedicated computing resources; as a result, RAID 5 & 6 arrays perform notably slower than their RAID 0 counterparts.

Customers that require additional security can opt for RAID 1/0.

RAID 1/0, which is also known as RAID 10, requires a minimum of 4 NVMe SSD’s – it will mirror the data of one stripe array to a second, hidden stripe array for security.

Unlike RAID 5, RAID 1/0 doesn’t necessitate additional parity related write operations, which reduce the TBW life span of NVMe SSD’s. In addition, a RAID 1/0 is capable of delivering read performance on par with a RAID 0 array.