In the step where you created your pool, you used the partition /dev/sda1 rather than the full drive /dev/sda. If ZFS for Linux ever escapes the FUSE layer, this usage is sub-optimal as ZFS understands when it has full use of the drive, and will adjust its caching and write behaviors accordingly. Basically, it knows that when the full write path to the drive is under its control, it can intelligently reorder the write packets to make optimal use of the bandwidth when sending packets to the drive so that head movement is minimized and such. This is not possible when a partition is used. Change: $ zpool create mypool /dev/sda1 To: $ zpool create mypool /dev/sda - kate »