Comment 3 for bug 308261

Here's maybe a better illustration of the problem.

Notice: copy operation on the array is about 25 MB/s (arry runs on different 2007 hdds, 30-35 should be normal today on hdds, 100+ on good SDDs), one kernel at 100% without stepping to the max. As one of the three disks makes about 25 MB/s each, for Raid 5 copy on the same array this is pretty OK, like copy from hdd1 to hdd2, with the xoring done without significant impact. I love Linux!