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I've bought a 1TB external hard drive and after formatting the entire drive in ext4 Nautilus says there are 934.3 GB of free space. enter image description here

I've also tested formatting the drive in XFS, and in this case there are 999.7 GB of free space.enter image description here

Why more than 60 GB are missing from free space with ext4 and not with XFS ?

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2 Answers

up vote 8 down vote

XFS and Ext4 filesystems have something called journaling.

Taken from Wikipedia:

A journaling file system is a file system that keeps track of the changes that will be made in a journal (usually a circular log in a dedicated area of the file system) before committing them to the main file system. In the event of a system crash or power failure, such file systems are quicker to bring back online and less likely to become corrupted.

The difference from both of them is that the maximum size for a XFS journal is 128MB while in ext4 it can take several gigabytes from your hard disk but it can be turned off if you do not care much about data integrity.

In the end its up to you and will always play with a mix of size occupied, data integrity and speed (non journal filesystems tend to be faster than filesystems with journaling turned on).

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up vote 8 down vote

EXT3/EXT4 filesystems take 5% of partition size for security etc. (e.g. in "non free disk space disk" cause).

If it isn't root partition, You could change this 5% to e.g. 1% by doing: 

sudo tune2fs -m 1 /dev/sda3

where you should change sda3 to your partition.

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1  
This space is not lost, by the way -- it is reserved for a single user, typically root. This is useful for example if you have a single partition and one user downloads the Internet (filling up the disk), system services can still write log files and audit information, keeping the system at least functional enough so an administrator can log in and examine the situation. For disks that will never contain anything relevant to the system, it is certainly acceptable to set this reservation to 0%. – Simon Richter Jul 26 '12 at 16:05

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