How to determine what allocation unit size was selected when a disk was formatted?
If a disk was formatted incorrectly i.e. a SQL Server data volume, but you want to check what allocation unit size was selected when the disk was formatted, use this…
From a CMD window, type FSUTIL FSINFO NTFSINFO <drive letter:>
e.g . FSUTIL FSINFO NTFSINFO D:
and look at the line: Bytes Per Cluster
The accepted rule for all SQL Server drives is 64K which reads as 65536 bytes