RAID 3
| RAID 3 provides disk striping and complete data redundancy though a dedicated parity drive. The |
| stripe size must be 64 KB if RAID 3 is used. RAID 3 handles data at the block level, not the byte |
| level, so it is ideal for networks that often handle very large files, such as graphic images. |
| RAID 3 breaks up data into smaller blocks, calculates parity by performing an |
| blocks, and then writes the blocks to all but one drive in the array. The parity data created during |
| the |
| by the stripe size parameter, which is set during the creation of the RAID set. |
| If a single drive fails, a RAID 3 array continues to operate in degraded mode. If the failed drive is |
| a data drive, writes will continue as normal, except no data is written to the failed drive. Reads |
| reconstruct the data on the failed drive by performing an |
| data in the stripe and the parity for that stripe. If the failed drive is a parity drive, writes will occur |
| as normal, except no parity is written. Reads retrieve data from the disks. |
Uses | Best suited for applications such as graphics, imaging, |
| video, or any application that calls for reading and writing |
| huge, sequential blocks of data. |
Strong Points | Provides data redundancy and high data transfer rates. |
Weak Points | The dedicated parity disk is a bottleneck with random I/O. |
Drives | Three to 32 |
Cont’d
Chapter 3 RAID Levels | 19 |