Today I did ran a few benchmarks to get a grasp of single-disk performance and to make sure the underlying storage sub-system is not acting as a bottleneck. Earlier I discovered a device incompatibility between the onboard (Asrock H77 Pro4-M) Intel SATA-3 ports and Intel X25-E disks which lead to COMRESET failed (errno=-16) messages during Linux boot. The fix was a simple cable swap with SATA-2 compatible ports 3-6.