With soft limits, whenever a user logs in with a usage greater than the assigned soft limit, that user is warned (by the login command). When the user exceeds the soft limit, the timer is enabled. Any time the quota drops below the soft limits, the timer is disabled. If the timer is enabled longer than a time period set by the administrators, the particular limit that has been exceeded is treated as if the hard limit has been reached, and no more resources are allocated to the user. The only way to reset this condition is to reduce usage below the quota. Only root may set the time limits and this is done on a per-filesystem basis.
Several options are available with the quotas subsystem. You can impose limits on some users and not others, some filesystems and not others, and on total disk usage per user, total number of files, or size of files. The system is completely configurable. You can also keep track of disk usage through the process accounting system provided under IRIX.
The importance of managing disk quotas carefully cannot be over emphasized. It is strongly recommended that if disk quotas are imposed, they should be soft quotas, and every attempt should be made to otherwise rectify the situation before removing someone's files. Before using the quotas subsystem to enforce disk usage, carefully read the material on disk quotas in the section "Disk Quotas" in this chapter.
The quotas system is described completely in the quotas(4) reference page. The procedure for imposing disk quotas is described in the section "Imposing Disk Quotas" in Chapter 5.