Mixing Hard Disk Drives of 512 Byte native and 512 Byte emulated Block Size in RAID Systems (1.4MB)
Hard Disk Drives (HDDs) for NAS and Enterprise Storage come in two different flavors of block size. Traditionally, the internal block size of HDDs is 512 byte, with 512 byte also used at the external interface. This technology is called 512 byte native, or 512n. Newer HDD models use an internal block size of 4k byte for higher storage efficiency, but still provide 512 byte at the external interface through a transparent emulation process. This technology is called 512 byte emulated (512e). Additionally drives with the 4k byte internal block format at the interface (4k byte native) are available, but these are rare and exclusively used in specific enterprise applications.