Search-Index: Best-Practises for formatting Index-Drive

Question

I recently discovered SRx-Core - a PowerShell-Toolset to troubleshoot SharePoint-Server Search.

The test 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.

Answer 1

My non-technical explanation: The index consumes a huge amount of disk space. Generally grabbing more space than it needs so that it can later shrink the contents in a merge operation. This write optimization benefits from bigger chunks of disk blocks because there is less latency cause by seeking data that is scattered in smaller chunks.