memory - RAID Lv 4 Parity -
how raid 4 right potential errors? understand has parity disk contains of parity bits, how go re-creating info of, say, disk 2 if destroyed?
the info recreated using parity info of course. calculation follows (for four-disk raid set):
disk 2 sector = (disk 1 sector) xor (disk 3 sector) xor (disk 3 sector) this means info of disk (including parity disk) can recovered using other disks. why array can handle single disk failure. same goes raid 5 same raid 4 distributes parity info across disks improved throughput.
the original paper introduced various raid levels read on reasoning behind , working of raid: http://www.cs.cmu.edu/~garth/raidpaper/patterson88.pdf
memory raid
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