Comments on: Automating DBCC DBTABLE – Obtaining the Disk Sector Size https://sqlsolutionsgroup.com/obtaining-the-disk-sector-size/ Thu, 21 Jul 2022 16:42:46 +0000 hourly 1 https://wordpress.org/?v=6.9.4 By: Jason Brimhall https://sqlsolutionsgroup.com/obtaining-the-disk-sector-size/#comment-56 Mon, 02 Nov 2015 19:23:20 +0000 http://sqlsolutionsgroup.com/?p=1975#comment-56 In reply to @sqL_handLe.

Thanks for correction. It is an important distinction and is clearly noted in the white paper.

Tracks are divided into sectors. A sector is the minimum chunk of data that can be read or written to a hard drive. Historically, sector size has been fixed at 512 bytes. Newer drives may offer 1 KB, 2 KB, or 4 KB sectors.
Many engineers will recognize file allocation unit by another name: cluster. Cluster size is determined when the partition is formatted by the operating system (or the user). For example, if the sectors of a hard drive are 512 bytes, a 4 KB cluster has 8 sectors, and a 64 KB cluster has 128 sectors.

]]> By: @sqL_handLe https://sqlsolutionsgroup.com/obtaining-the-disk-sector-size/#comment-55 Thu, 22 Oct 2015 15:45:35 +0000 http://sqlsolutionsgroup.com/?p=1975#comment-55 Hello!
Good stuff!
One correction: sector size is not the same as cluster/allocation unit size. Sector size is for communication with the device, most commonly 512bytes or 4k. 4k sector size devices are more recent. Allocation units or cluster size is a filesystem organization unit. Typically 4k or 64k.

You referenced the following white paper above.
https://msdn.microsoft.com/en-us/library/dd758814%28v=sql.100%29.aspx
In the whitepaper ‘fsutil fsinfo ntfsinfo’ example device sector size and filesystem cluster size are both indicated.

Bytes Per Sector : 512
Bytes Per Cluster : 65536

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