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 exclusive-or on the blocks, and then writes the blocks to all but one drive in the array. The parity data created during the exclusive-or is then written to the last drive in the array. The size of each block is determined 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 exclusive-or operation on the remaining 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.
Best suited for applications such as graphics, imaging, or video that call for reading and writing huge, sequential blocks of data.
Provides data redundancy and high data transfer rates. The dedicated parity disk is a bottleneck with random I/O. Three to eight
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