Craig Sanders wrote:
one error in 10^14 bits is nothing to worry about with 500GB drives. it's starting to get worrisome with 1 and 2TB drives. It's a guaranteed error with 10+TB arrays....and even a single 3 or 4TB drive has roughly a 30-50% chance of having at least one data error.
*nod* that's the root of my concern. And the "at least one" is the issue, because once a disk fails, if there's a second error somewhere then it WILL be encountered, because the rebuild has to traverse every sector of every remaining disk. Of course, that might not be enough to cause the rebuild (and thus the array) to fail. And there's probably another set of probabilities to factor in there too. But I can guarantee you a probability of 1.0 (with no deviation) that it will happen on the array that holds the critical data you need to recover that your boss accidentally forgot to back up... :)