Home > Storage > Unity XT > Storage Admin > Dell Unity: NAS Capabilities > Quota limits
All quotas consist of three major parameters which determine the amount of space that may be used in a file system in a certain scenario and define the behavior of the file system or directory when a limit is being approached or exceeded. These parameters are:
Each of these is configured during quota creation or inherited from the default settings for all quotas. The soft limit is a capacity threshold above which a countdown timer will begin. While the soft limit may be exceeded, this timer, or grace period, will continue to count down if the soft limit is exceeded. If the soft limit remains exceeded long enough for the grace period to expire, no new data may be added to the directory or by the particular user associated with the quota. However, if sufficient data is removed from the file system or directory to reduce the utilization below the soft limit before the grace period expires, access will be allowed to continue as usual. A hard limit is also set for each quota configured. Upon reaching a hard limit, no new data will be able to be added to the file system or directory. When this happens, the quota must be increased, or data must be removed from the file system before additional data can be added. The figure below illustrates this quota behavior.
Suppose the following user quota has been configured on a file system for a particular user: soft limit = 20 GB, grace period = 1 day, hard limit = 25 GB. The user begins copying data to the file system, and after some time the user has stored 16 GB of files on the file system. Because this is below the limits for the user’s quota, the user is still able to add more data to the file system unimpeded.
After some time, the user continues to add data to the file system, crossing the 20 GB soft limit. At this point the user is still able to add additional data to the file system, however the grace period of 1 day begins to count down. The storage administrator receives an alert in Unisphere stating that the soft quota for this user has been crossed. If the user does not remove data from the file system prior to the expiration of the grace period, they will no longer be able to add data to the file system until enough data is removed from the file system for the usage to fall below the soft limit.
However, if the user continues writing to and using additional space from the file system despite passing the soft limit, they may eventually reach the hard limit. When this happens, the user will no longer be able to add data to the file system. Administrators will also receive a warning in Unisphere informing them that the hard limit has been reached.
Starting with OE version 5.1, the quota grace period setting can be set to unlimited. The unlimited grace period setting should be used if write access should never be restricted, regardless of how long the grace period has been exceeded for. This setting allows administrators to use the soft limit setting for monitoring and warning purposes. The grace period can be changed at any time for both user and tree quotas.
The figure below shows a user quota which has exceeded its soft limit with an unlimited grace period.
The figure below shows multiple tree quotas that have exceeded the soft limit. The first tree quota has a limited and expired grace period while the second tree quota has an unlimited grace period.