How to verify that SQL Server is using the best practice NTFS Cluster Size


When planning the NTFS cluster size for a new volume the general consensus with the latest versions of Microsoft SQL Server is to use 64k.

So if you are auditing an existing installation, the following command-line utility can be used to query the NTFS file system to return whether this best practice was followed.

C:\Windows\system32>fsutil fsinfo ntfsinfo d:

NTFS Volume Serial Number :       0x32fe73cbfe7385bf
Version :                         3.1
Number Sectors :                  0x000000001beb87ff
Total Clusters :                  0x000000000037d70f
Free Clusters  :                  0x000000000037d1a9
Total Reserved :                  0x0000000000000000
Bytes Per 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
RM Identifier:        582D805C-3F5D-11E0-90B5-0017A4770826


You will notice that the result returned is slightly higher than 64k, and rounds up to 66k, but that is due to how storage is calculated and is the expected result when 64k is chosen from the format menu.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s