Disk allocation unit size

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

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