There is a reason why raid5 is generally a bad idea: when one drive fails then during the rebuild process of the array it happens sometimes that one other drive fails (because of the stress that rebuilding puts on the devices) hence causing unfixable data loss. I never understood what really is causing this ‘stress’ and I dont understand why rebuilding raid5 is more stressful than rebuilding say raid1 (that is cloning the surviving raid1 drive). Can someone explain?
In fact I read that this stress in the raid5 case is indeed due to continuous prolonged read, which also applies in the raid1 case; or for all that matter it should apply to cloning a disk with dd or ddrescue or gnome disks; or writing a large, say 4TB file, into a HDD; or reading a large file, say 4TB, from a certain HDD to compute its checksum.
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