RAID 0: data striping blocks are written sequentially, no redundancy, high performance than single disk access.
RAID 1: Mirroring, data blocks written to both disk at once, 100% redundancy, 100% additional capacity required. Read can be distributed across both the disks to increase performance.
RAID 3: Striping with byte parity, adds parity information to rebuild data in the event of disk failure, high transfer rate and availability with lower capacity required than RAID 1. Transactions performance low because all disks operate in lock step.
RAID 4: striping with block parity, independently accessible disks, data blocks written sequentially to each disk failure. Dedicated parity disk is write bottleneck and leads to poor performance.
RAID 5: Striping with rotational parity, parity blocks written per row and distributed across all disks, parity distribution eliminates single write bottleneck overhead for parity calculation on write supplemented with parallel microprocessors or caching.
RAID 1: Mirroring, data blocks written to both disk at once, 100% redundancy, 100% additional capacity required. Read can be distributed across both the disks to increase performance.
RAID 3: Striping with byte parity, adds parity information to rebuild data in the event of disk failure, high transfer rate and availability with lower capacity required than RAID 1. Transactions performance low because all disks operate in lock step.
RAID 4: striping with block parity, independently accessible disks, data blocks written sequentially to each disk failure. Dedicated parity disk is write bottleneck and leads to poor performance.
RAID 5: Striping with rotational parity, parity blocks written per row and distributed across all disks, parity distribution eliminates single write bottleneck overhead for parity calculation on write supplemented with parallel microprocessors or caching.
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