How do I determine the block size of an ext3 partition on Linux?
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8 Answers
# tune2fs -l /dev/sda1 | grep -i 'block size'
Block size: 1024
Replace /dev/sda1 with the partition you want to check.
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).
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3Don't forget the dot at the end of that command as
stat -fis expecting is expecting a folder to give you stats about. Jan 9, 2017 at 0:11 -
And to further narrow it down to what the OP asked for:
stat --printf='%s' -f .May 19, 2017 at 15:01 -
1
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1@JaniUusitalo, @c4f4t0r: thanks for the hint, corrected the answer using
-cwhich is simpler than--printf='...\n'– mikMar 28, 2018 at 14:14
dumpe2fs -h /dev/md2
will output something with:
Block size: 4096
Fragment size: 4096
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
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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1This is the same on every platform, the largest block size is supported by ext2/3 is 4096 bytes. Jun 23, 2009 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.– wzzrdJun 23, 2009 at 12:44
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Wikipedia says it can be 8k: en.wikipedia.org/wiki/Ext3#Size_limits– dfrankowApr 25, 2012 at 22:41
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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.– wzzrdApr 26, 2012 at 8:03
To detect block size of required partition:
Detect partition name:
$ df -hfor example we have
/dev/sda1Detect block size for this partition:
$ sudo blockdev --getbsz /dev/sda1
stat <<Filename>>
will also give file size in blocks
Use
sudo dumpe2fs /dev/sda1 | grep "Block size"
where /dev/sda1 is the device partition. You can get it from lsblk