Beyond RAID

Beyond RAID.

RAID 0: Striping

Data is striped across (n) drives, which improves performance almost linearly with the number of drives, but at a steep cost in fault tolerance; a failure of any single striped drive renders the entire array unreadable.

raid-0-diagram.png

RAID 1: Mirroring

Data is written across (n) drives, which offers near-perfect redundancy at a slight performance decrease when writing — and at the cost of half your overall storage. As long as one drive in the mirror array survives, no data is lost.

raid-1-diagram.png

Raid 5: Parity

Data is written across (n) drives with a parity block. The array can tolerate one drive failure, at the cost of one drive in storage. There may be a serious performance penalty when writing (as parity and blocks are calculated), and when the array is rebuilding.

raid-5-diagram.png

Raid 6: Dual Parity

Data is written across (n) drives with two parity blocks. The array can tolerate two drive failures, at the cost of two drives in storage. There may be a serious performance penalty when writing (as parity and blocks are calculated), and when the array is rebuilding.

raid-6-diagram.png

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