On Wed, Nov 12, 2008 at 3:44 AM, lee <[EMAIL PROTECTED]> wrote: > Do you mean it is more likely that any one drive in the array fails when > you have more drives, or do you mean that it is more likely for a drive > in the array to fail when you have more drives? If drives fail more > often when being used in an array with more drives, what makes them > fail more often under those conditions?
It's purely a statistical property, not related to being in a RAID array. But if there's (say) a 5% chance for a given drive to fail on a given day, there's a 95% chance it won't fail. If you have two drives, the chance *both* won't fail is the chance of one not failing, times the chance of the other not failing -- 95% times 95%, or 90.25%. With 24, the chance of all the drives not failing is .95^24 or 29.2%. Of course I just made the rates up, the survival chances of individual drives are higher. But logic holds; the more drives you're watching, the more lucky you'd have to be for none of them to be a dud. -jeff -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
