The Linux kernel supports disk quotas if the support for quotas is compiled into it. The kernel configuration option is CONFIG_QUOTA=y. Most distributions include this option in their kernels.

There are four steps to enabling quotas on a file system.

1. Add the usrquota option to the /etc/fstab entry
2. Use quotacheck filesystem to create initial quota files
3. Use edquota to set quota limits for users/groups
4. Enable quotas with quotaon filesystem

 

Quota files (binary)

Two quota files are stored in the root of the file system where they apply. They are:

• quota.user (v1) or aquota.user (v2)/li>
• quota.group (v1) or aquota.group (v2)

 

To set quotas for a user:

edquota -u user

To set quotas for a many users based on a another user:

edquota -p protouser -u user [user]

To set quotas for a group:

edquota -g group

To see a summary report on all quotas

repquota -a

To disable quotas:

quotaoff filesystem

To scan/update/repair quota files (unmount file system first):

quotacheck -u -g

Hard and Soft Limits

There are two limits that are enforced in the quota system. The first is a limit on the total amount of space used by all files owned by the user (block limit). The second is a limit on the maximum number of inodes used (file limit). Each limit has a soft (warning level) and hard limit (stop level). If a user exceeds the soft level, they have a grace period (7 days) to correct the problem. When they hit the hard limit, the system will not allocate any more space to them until they remove some files.