Musings, mutterings and murmurings
Linux allows setting quotas on a filesystem. This will prevent users from using more diskspace than they are allowed. This can also be used to manage group allowances to enforce the allowance for a collection of users. Stopping users from filling up a diskspace can be an important on a shared system as filling up a physical disk drive can bring a system down, or make it unstable.
Initially, you will need to mount a filesystem with a 'usrquota' or 'groupquota' command passed in /etc/fstab. After these have been applied, you will need to remount the drive for the quota to be effective.
/dev/sda3 /home ext4 defaults,usrquota 1 1 $ sudo mount -o remount /home
Next, run quotacheck on the filesystem to set up quotas.
$ sudo quotacheck -vu /home
Then, set the quotas as active with quotaon
$ sudo quotaon -vu /home
Finally, edit the quota for each user with edquota
$ sudo edquota someusername
You can also add grace periods with edquota, which allows users to plan for their storage needs if they exceed it with a time limit on moving their data.
When using edquota if you set a limit to 0 then this will mean that no limit will be enforced for that user or group.