> The more drives you have the more likely one of them to have a failure and once one fails and since the rebuild time increases with size your chance of failur

> The more drives you have the more likely one of them to have a failure and once one fails and since the rebuild time increases with size your chance of failure during rebuild increases as well. That was exactly what I was saying. Given the same sustained transfer rate, the bigger the drive, the longer the rebuild time, hence the greater the chance you'll have a failure during the rebuild. While you might think they would, throughput increases have not grown to match increases in bit density & storage capacity. SSD's have helped a bit in this area because their failure profiles are different and under the covers they are kind of like a giant array of mini devices, but AFAIK they still present challenges during RAID rebuilds.