Although HDD storage densities have increased dramatically over the years, one of the most elemental aspects of hard disk drive design, the logical block format size known as a sector, has remained constant. Beginning in late 2009, accelerating in 2010 and hitting mainstream in 2011, all major manufacturers are migrating away from the legacy sector size of 512 bytes to a larger, more efficient sector size of 4096 bytes, generally referred to as 4k or AF (Advanced Format).

While researching the benefits and consequences of a 512→4k transition, many reports of “partition misalignment issues” were found, that could lead to a severe performance impact which led to a closer investigation to verify the alleged problem and the proposed correct partition alignment. The result is obvious: Misaligned partitions on 4k harddisks introduce a severe performance impact, in this test case by a factor of 5.5 (Aligned: 83MB/s vs. misaligned: 15.5MB/s).

→ Read more...