43

How do I determine the block size of an ext3 partition on Linux?

| improve this question | |
61
# tune2fs -l /dev/sda1 | grep -i 'block size'
Block size:               1024

Replace /dev/sda1 with the partition you want to check.

| improve this answer | |
30

Without root, without writing, and for any filesystem type, you can do:

stat -fc %s .

This will give block size of the filesystem mounted in current directory (or any other directory specified instead of the dot).

| improve this answer | |
  • 2
    Don't forget the dot at the end of that command as stat -f is expecting is expecting a folder to give you stats about. – BeowulfNode42 Jan 9 '17 at 0:11
  • And to further narrow it down to what the OP asked for: stat --printf='%s' -f . – Jani Uusitalo May 19 '17 at 15:01
  • with newlinestat --printf='%s\n' -f . – c4f4t0r Mar 28 '18 at 9:48
  • 1
    @JaniUusitalo, @c4f4t0r: thanks for the hint, corrected the answer using -c which is simpler than --printf='...\n' – mik Mar 28 '18 at 14:14
12
dumpe2fs -h /dev/md2

will output something with:

Block size:               4096
Fragment size:            4096
| improve this answer | |
7

On x86, a filesystem block is just about always 4KiB - the default size - and never larger than the size of a memory page (which is 4KiB).

| improve this answer | |
  • This is the same on every platform, the largest block size is supported by ext2/3 is 4096 bytes. – Dave Cheney Jun 23 '09 at 10:06
  • Thanks Dave! I learned something today ;-) I originally thought the ext3 blocksize could be 8k on platforms that supported 8k memory pages. – wzzrd Jun 23 '09 at 12:44
  • Wikipedia says it can be 8k: en.wikipedia.org/wiki/Ext3#Size_limits – dfrankow Apr 25 '12 at 22:41
  • 1
    @dfrankow: if you have 8k memory pages, such as on Alpha hardware, yes. But you do not have those on x86 hardware and that is what I was talking about. – wzzrd Apr 26 '12 at 8:03
6

In the case where you don't have the right to run tune2fs on a device (e.g. in a corporate environment) you can try writing a single byte to a file on the partition in question and check the disk usage:

echo 1 > test
du -h test
| improve this answer | |
3

To detect block size of required partition:

  1. Detect partition name:

    $ df -h

    for example we have /dev/sda1

  2. Detect block size for this partition:

    $ sudo blockdev --getbsz /dev/sda1
| improve this answer | |
0
stat <<Filename>>

will also give file size in blocks

| improve this answer | |
  • This is not what the OP asked – Pablo A Jul 3 '19 at 7:55
0

Use

sudo dumpe2fs /dev/sda1 | grep "Block size"

where /dev/sda1 is the device partition. You can get it from lsblk

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.