Quotas provide a way to restrict or track the disk space and number of files used by a user, group, or qtree. You specify quotas using the /etc/quotas file.
Why you use quotas
You can use quotas to limit resource usage, to provide notification when resource usage reaches specific levels, or to track resource usage.
Overview of the quota process
Quotas can be soft or hard. Soft quotas cause Data ONTAP to send a notification when specified thresholds are exceeded, and hard quotas prevent a write operation from succeeding when specified thresholds are exceeded.
Quota targets and types
Quotas have a type: they can be either user, group, or tree. Quota targets specify the user, group, or qtree for which the quota limits are applied.
Special kinds of quotas
You use default, explicit, derived and tracking quotas to manage disk usage in the most efficient manner.
How quotas are applied
Understanding how quotas are applied enables you to configure quotas and set the expected limits.
How quotas work with users and groups
When you specify a user or group as the target of a quota, the limits imposed by that quota are applied to that user or group. However, some special groups and users are handled differently. There are different ways to specify IDs for users, depending on your environment.
How quotas work with qtrees
You can create quotas with a qtree as their target; these quotas are called tree quotas. You can also create user and group quotas for a specific qtree. In addition, quotas for a volume are sometimes inherited by the qtrees contained by that volume.
How qtree changes affect quotas
When you delete, rename, or change the security style of a qtree, the quotas applied by Data ONTAP might change, depending on the current quotas being applied.
How the quotas file works
The quotas file, found in the /etc directory, contains one or more entries specifying limit or tracking quotas for qtrees, groups, and users. The file can contain default (general) and specific entries.
How quotas are activated
New quotas and changes to quotas do not take effect until they are activated. Knowing how quota activation works can help you manage your quotas less disruptively.
How quota reports work
Quota reports enable you to see what quotas Data ONTAP is applying. You can change the format of the quota report and how user IDs are displayed using the options for the quota report command.
Difference in space usage displayed by a quota report and a UNIX client The value of used disk space that is displayed in a quota report for a volume or qtree can be different from the value displayed by a UNIX client for the same volume or qtree. The difference in usage values is because of the difference in methods followed by the quota report and the UNIX commands for calculating the data blocks in the volume or qtree.