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从概念上讲, RAID2 同RAID3类似, 两者都是将数据条块化分布于不同的硬盘上, 条块单位为位或字节。然而RAID2 使用称为“加重平均纠错码”的编码技术来提供错误检查及恢复。这种编码技术需要多个磁盘存放检查及恢复信息, 使得RAID2技术实施更复杂。 因此,在商业环境中很少使用。

RAID2: Hamming Code ECC

Characteristics/Advantages

1. “On the fly” data error correction

2. Extremely high data transfer rates possible

3. The higher the data transfer rate required, the better the ratio of data disks to ECC disks

4. Relatively simple controller design compared to RAID levels 3,4 & 5

Disadvantages

1. Very high ratio of ECC disks to data disks with smaller word sizes - inefficient

2. Entry level cost very high - requires very high transfer rate requirement to justify

3. Transaction rate is equal to that of a single disk at best (with spindle synchronization)

4. No commercial implementations exist / not commercially viable

Each bit of data word is written to a data disk drive (4 in this example: 0 to 3). Each data word has its Hamming Code ECC word recorded on the ECC disks. On Read, the ECC code verifies correct data or corrects single disk errors.