Menu
Right-click the drive and click "format", and the pop-up window will show the current cluster size under "allocation unit size".
Press Windows key + E to open File Explorer. Right-click on the partition you want to change cluster size, select Format. Click Allocation Unit Size (Cluster size). Select one cluster size you want to change to from the drop-down.
As designed, the maximum NTFS file size is 16 EB (16 × 10246 bytes) minus 1 kB or 18,446,744,073,709,550,592 bytes. As implemented, the maximum NTFS file size is 16 TB minus 64 kB or 17,592,185,978,880 bytes.
Open an administrator command prompt, and do this command:
fsutil fsinfo ntfsinfo [your drive]
The Bytes Per Cluster is the equivalent of the allocation unit.
Use diskpart.exe.
Once you are in diskpart select volume <VolumeNumber> then type filesystems.
It should tell you the file system type and the allocation unit size. It will also tell you the supported sizes etc. Previously mentioned fsutil does work, but answer isn't as clear and I couldn't find a syntax to get the same information for a junction point.
Another way to find it quickly via the GUI on any windows system:
create a text file, type a word or two (or random text) in it, and save it.
Right-click on the file to show Properties.
"Size on disk" = allocation unit.
I know this is an old thread, but there's a newer way then having to use fsutil or diskpart.
Run this powershell command.
Get-Volume | Format-List AllocationUnitSize, FileSystemLabel
The value for BYTES PER CLUSTER - 65536 = 64K
C:\temp>fsutil fsinfo drives
Drives: C:\ D:\ E:\ F:\ G:\ I:\ J:\ N:\ O:\ P:\ S:\
C:\temp>fsutil fsinfo ntfsInfo N:
NTFS Volume Serial Number : 0xfe5a90935a9049f3
NTFS Version : 3.1
LFS Version : 2.0
Number Sectors : 0x00000002e15befff
Total Clusters : 0x000000005c2b7dff
Free Clusters : 0x000000005c2a15f0
Total Reserved : 0x0000000000000000
Bytes Per Sector : 512
Bytes Per Physical Sector : 512
Bytes Per Cluster : 4096
Bytes Per FileRecord Segment : 1024
Clusters Per FileRecord Segment : 0
Mft Valid Data Length : 0x0000000000040000
Mft Start Lcn : 0x00000000000c0000
Mft2 Start Lcn : 0x0000000000000002
Mft Zone Start : 0x00000000000c0000
Mft Zone End : 0x00000000000cc820
Resource Manager Identifier : 560F51B2-CEFA-11E5-80C9-98BE94F91273
C:\temp>fsutil fsinfo ntfsInfo N:
NTFS Volume Serial Number : 0x36acd4b1acd46d3d
NTFS Version : 3.1
LFS Version : 2.0
Number Sectors : 0x00000002e15befff
Total Clusters : 0x0000000005c2b7df
Free Clusters : 0x0000000005c2ac28
Total Reserved : 0x0000000000000000
Bytes Per Sector : 512
Bytes Per Physical Sector : 512
Bytes Per Cluster : 65536
Bytes Per FileRecord Segment : 1024
Clusters Per FileRecord Segment : 0
Mft Valid Data Length : 0x0000000000010000
Mft Start Lcn : 0x000000000000c000
Mft2 Start Lcn : 0x0000000000000001
Mft Zone Start : 0x000000000000c000
Mft Zone End : 0x000000000000cca0
Resource Manager Identifier : 560F51C3-CEFA-11E5-80C9-98BE94F91273
Easiest way, confirmed on 2012r2.
Under drop down "allocation unit size" will be the value of what the Allocation of the Unit size disk already is.
According to Microsoft, the allocation unit size "Specifies the cluster size for the file system" - so it is the value shown for "Bytes Per Cluster" as shown in:
fsutil fsinfo ntfsinfo C:
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With