Assuming a sane RAID situation, e.g. data being duplicated onto multiple drives. If one of those drives fails, making additional duplicates onto the surviving d

Assuming a sane RAID situation, e.g. data being duplicated onto multiple drives. If one of those drives fails, making additional duplicates onto the surviving drives, or rebuilding the data of the failed drive onto a new drive. Can also be done with tapes, but you would require multiple tape drives (though if you can afford an automated library, thats probably nothing in comparison), additionally you can't find the failures until you take them out of "cold" storage. If you can respond to the first failure when it happens, you can react before being hit by later failures hitting the duplicates. Downside is, since you have active components, failures are expected to be more common.