I recently discovered SRx-Core - a PowerShell-Toolset to troubleshoot SharePoint-Server Search.
OSVolumeProperties recommends a NTFS-Blocksize of 64 Kilobytes for index data volumes:
OSVolumeProperties Warning Index data volumes have configuration settings which do not follow recommended guidance The following may cause performance issues:The following may cause performance issues: * The index data volume I: on server XXX has a block size of 4096 - Formatting this volume with a 64KB block size is recommended for better performance
I was not able to find any documentation to that recommendation. Would be great if someone could provide some background.