<p>Which built in (if any) tool can I use to determine the allocation unit size of a certain NTFS partition ?</p>

[{'answer_id': 81257, 'author': 'William', 'author_id': 14829, 'author_profile': 'https://Stackoverflow.com/users/14829', 'pm_score': 8, 'selected': True, 'text': '<p>Open an administrator command prompt, and do this command:</p>\n\n<pre><code>fsutil fsinfo ntfsinfo [your drive]\n</code></pre>\n\n<p>The Bytes Per Cluster is the equivalent of the allocation unit. </p>\n'}, {'answer_id': 3561054, 'author': 'steven', 'author_id': 430037, 'author_profile': 'https://Stackoverflow.com/users/430037', 'pm_score': 6, 'selected': False, 'text': "<p>Use <code>diskpart.exe</code>.</p>\n\n<p>Once you are in diskpart <code>select volume &lt;VolumeNumber&gt;</code> then type <code>filesystems</code>.</p>\n\n<p>It should tell you the file system type and the allocation unit size.  It will also tell you the supported sizes etc. Previously mentioned <code>fsutil</code> does work, but answer isn't as clear and I couldn't find a syntax to get the same information for a junction point.</p>\n"}, {'answer_id': 13600516, 'author': 'eadmaster', 'author_id': 791229, 'author_profile': 'https://Stackoverflow.com/users/791229', 'pm_score': 1, 'selected': False, 'text': '<p>from the commandline:</p>\n\n<p>chkdsk l: (wait for the scan to finish)</p>\n\n<p>sizdir32 <a href="http://www.ltr-data.se/opencode.html/" rel="nofollow">http://www.ltr-data.se/opencode.html/</a></p>\n'}, {'answer_id': 13905409, 'author': 'robertcollier4', 'author_id': 1781201, 'author_profile': 'https://Stackoverflow.com/users/1781201', 'pm_score': 2, 'selected': False, 'text': '<p>According to <a href="http://technet.microsoft.com/en-us/library/cc722475.aspx" rel="nofollow">Microsoft</a>, 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:</p>\n\n<pre><code>fsutil fsinfo ntfsinfo C:\n</code></pre>\n'}, {'answer_id': 17445933, 'author': 'Kunal Mudliyar', 'author_id': 2546175, 'author_profile': 'https://Stackoverflow.com/users/2546175', 'pm_score': -1, 'selected': False, 'text': '<p>start > run > MSINFO32 </p>\n\n<p>goto components </p>\n\n<p>goto storage</p>\n\n<p>goto disk</p>\n\n<p>on the right look for Bytes/Sector</p>\n'}, {'answer_id': 18663186, 'author': 'J Y', 'author_id': 2755186, 'author_profile': 'https://Stackoverflow.com/users/2755186', 'pm_score': 4, 'selected': False, 'text': '<p>Another way to find it quickly via the GUI on any windows system:</p>\n\n<ol>\n<li><p>create a text file, type a word or two (or random text) in it, and save it.</p></li>\n<li><p>Right-click on the file to show Properties.</p></li>\n<li><p>"Size on disk" = allocation unit.</p></li>\n</ol>\n'}, {'answer_id': 23573215, 'author': 'Markus', 'author_id': 1332129, 'author_profile': 'https://Stackoverflow.com/users/1332129', 'pm_score': 2, 'selected': False, 'text': '<p>You can use SysInternals <a href="http://technet.microsoft.com/en-us/sysinternals/bb897424.aspx" rel="nofollow noreferrer">NTFSInfo</a> by Mark Russinovich from the command line and it converts fsutil fsinfo ntfsinfo into more readable information, especially MFT Table info.</p>\n'}, {'answer_id': 35299012, 'author': 'Aman Arora', 'author_id': 5904669, 'author_profile': 'https://Stackoverflow.com/users/5904669', 'pm_score': 3, 'selected': False, 'text': '<p>The value for BYTES PER CLUSTER - 65536 = 64K</p>\n\n<pre><code>C:\\temp&gt;fsutil fsinfo drives\n\nDrives: C:\\ D:\\ E:\\ F:\\ G:\\ I:\\ J:\\ N:\\ O:\\ P:\\ S:\\\n\nC:\\temp&gt;fsutil fsinfo ntfsInfo N:\nNTFS Volume Serial Number :       0xfe5a90935a9049f3\nNTFS Version   :                  3.1\nLFS Version    :                  2.0\nNumber Sectors :                  0x00000002e15befff\nTotal Clusters :                  0x000000005c2b7dff\nFree Clusters  :                  0x000000005c2a15f0\nTotal Reserved :                  0x0000000000000000\nBytes Per Sector  :               512\nBytes Per Physical Sector :       512\nBytes Per Cluster :               4096\nBytes Per FileRecord Segment    : 1024\nClusters Per FileRecord Segment : 0\nMft Valid Data Length :           0x0000000000040000\nMft Start Lcn  :                  0x00000000000c0000\nMft2 Start Lcn :                  0x0000000000000002\nMft Zone Start :                  0x00000000000c0000\nMft Zone End   :                  0x00000000000cc820\nResource Manager Identifier :     560F51B2-CEFA-11E5-80C9-98BE94F91273\n\nC:\\temp&gt;fsutil fsinfo ntfsInfo N:\nNTFS Volume Serial Number :       0x36acd4b1acd46d3d\nNTFS Version   :                  3.1\nLFS Version    :                  2.0\nNumber Sectors :                  0x00000002e15befff\nTotal Clusters :                  0x0000000005c2b7df\nFree Clusters  :                  0x0000000005c2ac28\nTotal Reserved :                  0x0000000000000000\nBytes Per Sector  :               512\nBytes Per Physical Sector :       512\nBytes Per Cluster :               65536\nBytes Per FileRecord Segment    : 1024\nClusters Per FileRecord Segment : 0\nMft Valid Data Length :           0x0000000000010000\nMft Start Lcn  :                  0x000000000000c000\nMft2 Start Lcn :                  0x0000000000000001\nMft Zone Start :                  0x000000000000c000\nMft Zone End   :                  0x000000000000cca0\nResource Manager Identifier :     560F51C3-CEFA-11E5-80C9-98BE94F91273\n</code></pre>\n'}, {'answer_id': 40792648, 'author': 'LinusSch', 'author_id': 5545874, 'author_profile': 'https://Stackoverflow.com/users/5545874', 'pm_score': 2, 'selected': False, 'text': '<p>The simple GUI way, as provided by J Y in a previous answer:</p>\n\n<ol>\n<li>Create a small file (not empty)</li>\n<li>Right-click, choose Properties</li>\n<li>Check "Size on disk" (in tab General), double-check that your file size is less than half that so that it is certainly using a single allocation unit.</li>\n</ol>\n\n<p>This works well and reminds you of the significance of allocation unit size. But it does have a caveat: as seen in comments to previous answer, Windows will sometimes show "Size on disk" as 0 for a very small file. In my testing, NTFS filesystems with allocation unit size 4096 bytes required the file to be 800 bytes to consistently avoid this issue. On FAT32 file systems this issue seems nonexistent, even a single byte file will work - just not empty.</p>\n'}, {'answer_id': 49454825, 'author': 'SQLing4ever', 'author_id': 8507689, 'author_profile': 'https://Stackoverflow.com/users/8507689', 'pm_score': 5, 'selected': False, 'text': "<p>I know this is an old thread, but there's a newer way then having to use fsutil or diskpart.</p>\n\n<p>Run this powershell command.</p>\n\n<p><code>Get-Volume  | Format-List AllocationUnitSize, FileSystemLabel</code></p>\n"}, {'answer_id': 62155278, 'author': 'Topsy K', 'author_id': 13666428, 'author_profile': 'https://Stackoverflow.com/users/13666428', 'pm_score': 3, 'selected': False, 'text': '<p>Easiest way, confirmed on 2012r2.</p>\n\n<ol>\n<li>Go to "This PC"</li>\n<li>Right click on the Disk</li>\n<li>Click on Format</li>\n</ol>\n\n<p>Under drop down "allocation unit size" will be the value of what the Allocation of the Unit size disk already is.</p>\n'}, {'answer_id': 68730990, 'author': 'Khalil Al-rahman Yossefi', 'author_id': 5827730, 'author_profile': 'https://Stackoverflow.com/users/5827730', 'pm_score': 2, 'selected': False, 'text': '<p>In a <code>CMD</code> (as adminstrator), first run <code>diskpart</code>. In the opened program, enter <code>list disk</code>. It\'ll list all connected disks.\n<a href="https://i.stack.imgur.com/b22Qm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/b22Qm.png" alt="list disk" /></a></p>\n<p>Select the right disk based on its size. If it is flash memory, usually it\'d be the last item in the list. In my case, I select the <code>Disk 2</code> using this command: <code>select disk 2</code>.</p>\n<p>After selecting your disk, list the partitions using <code>list partion</code> command. You\'ll get a list like the one in the image below.\n<a href="https://i.stack.imgur.com/4uTsr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4uTsr.png" alt="list partition" /></a></p>\n<p>Now, it is time to select the right partition, based on its size. In my case, I select Partition 1 using this command: <code>select partition 1</code>.</p>\n<p>Finally, you can run the <code>filesystem</code> command to get the <code>Allocation Unit Size</code>.\n<a href="https://i.stack.imgur.com/0265T.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0265T.png" alt="Allocation Unit Size" /></a></p>\n<p>Note: This procedure works on both <strong>NTFS</strong> and <strong>FAT32</strong>.</p>\n'}]
['https://Stackoverflow.com/questions/81236', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/-1/']