Get More Space Out of Your ext3 Partition

I have just discovered that ext3 defaults to reserving 5% of its partition exclusively for root, as a precaution measure that your system does not get FUBAR when you use it for your root partition. I have a 230GB external USB disk that I use for all my big storage requirements, downloaded stuff, backups etc. Due to this reservation I had 11.5GB of unusable disk space, thankfully this is easy to fix:

Replace sdf1 with your partition name. You don’t even have to unmount your disk. Voilรก, 11.5 GB more space for free ๐Ÿ™‚ Here is the output of df -h as proof:



If you like this, you might also be interested in How to change Ubuntu forced fsck.

Update: The free space limitation is also used to prevent fragmentation. So if you set the limit to zero and operate on a very full harddisk for a while, your filesystem might slow down.

10 Comments on "Get More Space Out of Your ext3 Partition"

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this is awesome!! i was wondering why the data on my 500 gig drive wouldnt fit back on the same drive once it was changed from ntfs to ext3. mystery solved.. ๐Ÿ™‚

Thomas Einwaller

Nice tip! I got some partitions where I could use that too …


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[…] First I create the physical volume on the partition sdg1, create a new volume group ext_vg that contains this physical volumen, and create a new logical volume of size 450GB within thie volume group. Finally create the filesystem (disabled reservation space, see Get More Space Out of Your ext3 Partition). […]


Very awesome find! I can’t believe I never knew about this. In my particular case, I just reduced the reserved blocks to 3% (-m 3), which gives me a few extra gigs.

Thanks for the post!


Yeah I wouldn’t recommend doing this at all. That reserved space is to reduce disk file fragmentation so if you fill it up then your filesystem will be very fragmented if it is always full. Please update your blog saying this so not everyone makes it 0% ๐Ÿ™‚

Martin Ankerl

Hi MistaED, I have updated the blog with a little warning


Where do I paste ‘tune2fs -m 0 /dev/sdf1’? Or what do I do with it, my computer only holds 18.35 gigs X_x so yea..

Martin Ankerl

yang, open e.g. gnome-terminal. But please read something about how the command line works before just copy & pasting commands, this can be dangerous when you do not know what you are doing…
Here is a link:

Kunal Gautam

Stumbled and Faved in my Bookmark . It really helped . Thanks for sharing