Quotas are not enabled by default, even if the quota software package is installed on your Ubuntu system. When quotas are installed and enabled, you can see which partitions have either user quotas, group quotas, or both by looking at the fourth field in the
/etc/fstab file. For example, one line in
/etc/fstab shows that quotas are enabled for the
/dev/hda5 /home ext3 defaults,usrquota,grpquota 1 1
The root of the partition with quotas enabled will have the files
quota.group in them (or both files, if both types of quotas are enabled), and the files will contain the actual quotas. The permissions of these files should be
600 so that users cannot read or write to them. (Otherwise, ...