I wanted to try out the new GPT system, and used it to partition my new HDD, with the partitions themselves using ext4. For some reason, about 1-2% of the space in each partition is already shown as used, both in df and gparted. Currently the only content of the partitions is the lost+found folder which occupies all of 16K.

Is there a reason for this? Can this be fixed? Or is this just the space used by the file table (or equivalent)?

Edit: Is this more related ext4 than GPT? I found this just now, ext4: How to account for the filesystem space?


1-5% is reserved for root and as overhead for the filesystem. It is NORMAL. This is done is to leave root that 1-5% so if the users on the machine fill the disk up, critical system processes and the root user still have a small chunk to play with. As jordanm pointed out, the reserved space is also used to reduce filesystem fragmentation.

You can use tune2fs -m 1.0 /dev/sda2 to lower the default 5% to 1%. Please note that it is not recommended to use -m 0 but still can be done.

  • I think you are mixing up things. The reserved space is proper disk space reserved to the UID 0, whereas the file system structures are meta-data and not normally shown. Feb 20 '13 at 14:30
  • Was in the process of editing my answer, thanks though.
    – h3rrmiller
    Feb 20 '13 at 14:32
  • 2
    The reserved space is also used to reduce fragmentation.
    – jordanm
    Feb 20 '13 at 14:33

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