SQL Server and Windows on the same disk (allocation unit size 64kb-4kb)

Copper Contributor


I am running a server with SQL server with 2 x 960GB NVME Datacenter SSD in RAID1, windows files and database and default database files on the same disk.

This server is using the default format allocation size 4Kb.

I have read that 64Kb is better for SQL and this server is only hosting SQL server.

Should I reformat the server and reinstall Windows 2019 server with 64Kb allocation size ?


Thank you!

1 Reply

@egyteam , SQL Server use data pages = 8 kbyte, it always reads "Extents" = 8 page = 64 kbytes from disks, therefore it's always suggested to format disks for SQL Server data files in that size.


But in times of such fast SSD you won't notice a difference, so I wouldn't make efforts to reformat the disk.


see Pages and Extents Architecture Guide - SQL Server | Microsoft Docs