Linux – Reduce Space Usage of ext-Filesystems

ext2ext3ext4filesystemslinux

I have a bunch of external and internal HDDs that I use on a Linux system. I only have Linux systems, so using a Linux file-system would only make sense, right? However I'm currently using NTFS everywhere, because it gives me the most usable space out of HDDs.

I would like to switch to Linux file-systems now though, mostly because of permissions and compability (e.g. I can't get my LUKS encrypted NTFS partition to resize under Linux, keeps telling me to chkdsk under Windows).

However when I formatted those HDDs I tried out a bunch of different filesystems and every Linux filesystem, even ext2 which as far as I know has no journaling, used a lot of space for itself. I don't recall exact values, but it was over 100GB that NTFS got me more on a 2TB HDD, which is a lot.

So my question is: Is there a way to make ext-filesystems use less space for themselves? Or is there another filesystem (I've tried ext2, ext3, ext4, NTFS and vfat – None of them came even close to the usable space NTFS offered me) with perfect Linux support and great usable space?

I'd love to hear about how and why filesystems (especially ext2 which has no journaling) use that much more space than NTFS and I don't know where else to ask. I'd mostly prefer a way to use ext4 without journaling and anything else that uses up this much space, if that's possible.

Best Answer

By default, ext2 and its successors reserve 5% of the filesystem for use by the root user. This reduces fragmentation, and makes it less likely that the administrator or any root-owned daemons will be left with no space to work in.

These reserved blocks prevent programs not running as root from filling your disk. Whether these considerations justify the loss of capacity depends on what the filesystem is used for.

The 5% amount was set in the 1980s when disks were much smaller, but was just left as-is. Nowadays 1% is probably enough for system stability.

The reservation can be changed using the -m option of the tune2fs command:

tune2fs -m 0 /dev/sda1

This will set the reserved blocks percentage to 0% (0 blocks).

To get the current value (among others), use the command :

tune2fs -l <device>
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