Determine OS block size for Linux and Windows

A block is a uniformly sized unit of data storage for a filesystem. Block size can be an important consideration when setting up a system that is designed for maximum performance. 

Block size in Linux :  If we want to confirm the block size of any filesystem of Ubuntu or any other Linux OS, tune2fs command is here to help:

ubuntu# tune2fs -l /dev/sda1 | grep Block
Block count:              4980736
Block size:                 4096
Blocks per group:       32768

From this example, we can see that the default block size for the filesystem on  /dev/sda1 partition is 4096 bytes, or 4k. That's the default block size for ext3 filesystem.

OS block size in Solaris : 

$perl -e '$a=(stat ".")[11]; print $a'
8192

or 
$df -g | grep 'block size' 

Block size in Window Machine  : If  OS  is using ntfs system use the below command  :

C:\>fsutil fsinfo ntfsinfo D:
NTFS Volume Serial Number :        0x7a141d52141d12ad
Version :                                          3.1
Number Sectors :                            0x00000000036b17d0
Total Clusters :                                0x00000000006d62fa
Free Clusters  :                               0x00000000001ed190
Total Reserved :                             0x0000000000000170
Bytes Per Sector  :                         512
Bytes Per Cluster :                     4096   <<===   (block size)
Bytes Per FileRecord Segment       : 1024
Clusters Per FileRecord Segment   : 0
Mft Valid Data Length :                    0x0000000005b64000
Mft Start Lcn  :                                 0x00000000000c0000
Mft2 Start Lcn :                                0x000000000036b17d
Mft Zone Start :                                0x000000000043c9c0
Mft Zone End   :                               0x000000000044b460

or we can also find the block size as : 

--> Go to "My Computer"   --> manage --> Disk Defragmenter --> select any disk -->  click on "analyze" button , then it will present us a report and in that report "Cluster Size" represents the  OS "Block Size".

Enjoy   :-)