I created a zip archive named tmp.zip.

It has a size

$ du -h tmp.zip
1.7G    tmp.zip

I copied it to flash drive

$ du -h /media/tb/tmp.zip 
1.5G    /media/tb/tmp.zip

What's wrong here? How can I check what is missing in the archive on the flash drive if something is missing?

  • 2
    du's not the best for checking if files are the same. Compute a checksum (md5sum or similar).
    – Mat
    Dec 19, 2016 at 12:14

1 Answer 1


The two filesystems most probably use different blocksize, this can change the graininess with which filesizes can be assigned.

  • 1
    That is a very different block size to make one file ~200MB different. (I'm tempted to say impossibly different.) I suggest you add using stat or ls -s to confirm the logical size is the same.
    – derobert
    Dec 19, 2016 at 12:42
  • @derobert I copied it to SD card, the size was 1.7G and md5sum as Mat suggested was the same. I will try it with flash drive as well later.
    – xralf
    Dec 19, 2016 at 13:14
  • What filesystem did you use on flash disk?Did you try to extract 1.5 G zip file? any errors or ok ?1MB = 1000 KB or 1MB = 1024KB Did it cause a size different?
    – supriady
    Dec 19, 2016 at 15:09

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