How do I determine the block size of an ext3 partition on Linux?
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# tune2fs -l /dev/sda1 | grep -i 'block size'
Block size: 1024
Replace /dev/sda1 with the partition you want to check.
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Without root and without writing, one can do:
stat -fc %s .
This will give block size of the filesystem in current directory.
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2Don't forget the dot at the end of that command as
stat -fis 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 -
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1@JaniUusitalo, @c4f4t0r: thanks for the hint, corrected the answer using
-cwhich is simpler than--printf='...\n'– mik Mar 28 '18 at 14:14
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dumpe2fs -h /dev/md2
will output something with:
Block size: 4096
Fragment size: 4096
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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).
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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
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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
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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
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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
1
To detect block size of required partition:
Detect partition name:
$ df -h, f.e. we have /dev/sda1
Detect block size for this partition:
$ sudo blockdev --getbsz /dev/sda1
0
stat <<Filename>>
will also give file size in blocks
