RhinOS™ 25 — Secure Enterprise

Striping is the process of distributing blocks of data across hard drives. Input data is split up into pieces known as striped units. If you refer to this diagram, striped units Block 0 through Block 8 would be considered a stripe.

A single hard drive handles read and write operations one at a time. In contrast, a RAID 0 system enables parallel processing, allowing the system to perform read and write operations across multiple drives simultaneously. For example, the owner of a striped system can access Block 0, Block 1, and Block 2 at the same time, significantly improving performance.

Mirroring writes all data simultaneously to two drives, creating a 1-for-1 copy that offers the highest level of redundancy. This setup also delivers excellent read performance, as the system can access both drives in parallel. Write performance remains steady because both drives write the same data at the same time. However, RAID-1 comes with a higher cost since it requires double the storage capacity to mirror data. Traditional RAID-1 supports only two drives, which limits its scalability for larger storage needs.

RAIDZ provides redundancy by using parity, allowing data recovery without the need for full duplication on a second drive. It mathematically creates a new block of data across multiple disks, so if one drive fails, the RAID controller can reconstruct the missing data from the remaining drives. RAIDZ supports single parity, enabling the system to continue functioning even if a drive fails, with parity distributed across the disks to balance access and improve performance. While RAIDZ offers high storage capacity and reliability, performance is slightly reduced due to the calculations required for reading and writing data.

RAID-Z protects against a single drive failure and can actively rebuild the data. RAID-Z2 goes further by using two separate sets of parity calculations, allowing it to recover from two simultaneous drive failures—what’s known as N+2 redundancy. To function properly, RAID-Z2 requires at least four drives: two for data and two for parity. It performs best when used with a larger number of disks, though only to a certain point. As disk count increases, so does efficiency—but also the risk of multiple failures and the complexity of rebuilding. RAID-Z2 strikes a strong balance between capacity, redundancy, and performance, making it the preferred choice for high-capacity storage environments.

RAID-Z3 is the most advanced level of RAID-Z, offering triple-disk redundancy. It can withstand the failure of up to three disks without losing any data. RAID-Z3 is ideal for environments where data integrity is critical and cannot afford any data loss.