Using Disk Quotas
Most sysadmins have had a server system partition fill up due to one thing or another, usually followed closely by a system crash or kernel panic (and sysadmin panic). A package on nearly every Unix/Linux system, called quota, lets you limit disk usage on a per-user and per-filesystem basis.
One important limitation is that quotas are on a filesystem, not a directory tree. If you have two directory trees (/home and /var/www, for example) that need to have conflicting or different quotas, these directory trees must be on separate filesystems, which means separate partitions.
Quota Commands and Files
The quota system is designed ...