Reclaim Reserved Filesystem Space

Ext3 partition contain a used space of 5% for special reasons by default. The main reason for such space is so root can log in even when the filesystem becomes 100% used. Without this option, the root user might not be able to log in to "clean up" because the system could become unstable, trying to write logs to a 100% full system for example. The other reason is to help with less fragmentation on the filesystem.

The issue with this is that hard drives are getting so big the 5% can add up to be quite a large amount of wasted space. (eg. 100 GB = 5 GB reserved). Now if you separate your filesystems to like /home for example it might be a good idea to adjust these and reclaim that wasted space. It's a safe bet to leave your / filesystem at 5% reserved just in case. Leave reserved space for filesystems containing /var and /tmp also or else you'll end up with problems.

http://wiki.archlinux.org/index.php/Ext3_Filesyste m_Tips