Similar to firmware in 512e drives, this software emulation layer exposes 512 sectors to the guest operating system while using 4K native (4Kn) drives as local storage in a server. This approach enables running legacy operating systems, applications, and existing VMs on servers with 4Kn HDD drives. This support also gives you the flexibility of using new 4Kn hardware on your vSphere 6.7 host, but still run older applications in the host’s virtual machines.
To learn more about this new architecture in vSphere 6.7, see Support for 4Kn HDDs.
vSphere 6.7 includes software emulation for 4Kn drives
There was no perceivable difference in performance in random I/Os, reads or writes, irrespective of the percentage of 4 KB alignments in the I/O blocks. This test was focused on random I/O because, generally, an ESXi host with many virtual machines requires the storage to be optimized for a random I/O stream.