Their test is completely invalid, they only used a small portion of the disk in a sequential manner. Likely the "cache" portion of the array is a significant po

Their test is completely invalid, they only used a small portion of the disk in a sequential manner. Likely the "cache" portion of the array is a significant portion of the partition they created. Further, I'm not aware of a single raid system built in the last 20 years that doesn't do online rebuild. This means its only sequential IO as long as the RAID controller isn't servicing other IO requests. Futher it also assumes that your running a dead simple RAID system that is RAIDing the entire array rather than doing the RAID on top of a LVM/thin provisioning like setup (this is basically ZFS's problem). Frankly, I would be willing to bet that its possible to tweak a benchmark like iometer to use a sufficiently large part of the disk with a 50% random RW workload and cause quite a number of RAID controllers to kick the drives for write timeouts. Some percentage of them might even kick multiple disks at the same time resulting in complete array loss.