Once quotas are in place, they can be changed to adjust the
amount of disk space or the number of inodes that users can consume.
Additionally, quotas can be added or removed as system needs change. For instructions
on changing quotas or the amount of time that quotas can be exceeded,
disabling individual quotas, or removing quotas from file systems, see Changing and Removing Quotas.
In addition, quota status can be monitored. Quota commands enable administrators to display
information about quotas on a file system, or search for users who have
exceeded their quotas. For procedures that describe how to use these commands, see
Setting Soft Limits and Hard Limits for Quotas
You can set both soft limits and hard limits. The system does
not allow a user to exceed his or her hard limit. However, a
system administrator might set a soft limit, which the user can temporarily exceed.
The soft limit must be less than the hard limit.
Once the user exceeds the soft limit, a quota timer begins. While
the quota timer is ticking, the user is allowed to operate above the
soft limit but cannot exceed the hard limit. Once the user goes below
the soft limit, the timer is reset. However, if the user's usage remains
above the soft limit when the timer expires, the soft limit is enforced
as a hard limit. By default, the soft limit timer is set to
The timeleft field in the repquota and quota commands shows the value
of the timer.
For example, let's say a user has a soft limit of 10,000
blocks and a hard limit of 12,000 blocks. If the user's block usage
exceeds 10,000 blocks and the seven-day timer is also exceeded, the user cannot
allocate more disk blocks on that file system until his or her usage
drops below the soft limit.
The Difference Between Disk Block and File Limits
A file system provides two resources to the user, blocks for data
and inodes for files. Each file consumes one inode. File data is stored
in data blocks. Data blocks are usually made up of 1Kbyte blocks.
Assuming no directories exist, a user can exceed his or her inode
quota by creating all empty files without using any blocks. A user can
also use one inode, yet exceed his or her block quota, by creating
one file that is large enough to consume all the data blocks in
the user's quota.