In order to implement Disk Quota on Linux Systems, you would need to remount the file system with usrquota and grpquota options.

vi /etc/fstab

/dev/VolGroup00/LogVol02 /home ext3 defaults,usrquota,grpquota 1 2

mount -o remount /home

The next step is to initialize the quota database :

quotacheck -cug /home

Now Generate the table of current disk usage :

quotacheck -avug

In order to assign quota to a user run :

edquota username

Verify User Quota has been set :

quota testuser