System Administration Guide: Advanced Administration

Setting Up Quotas

Setting up quotas involves these general steps:

Ensuring that quotas are enforced each time the system is rebooted by adding a quota option to the /etc/vfstab file entries. Also, creating a quotas file in the top-level directory of the file system.
After you create a quota for one use, copying the quota as a prototype to set up other user quotas.
Before you turn quotas on, checking the consistency of the proposed quotas with the current disk usage to make sure that there are no conflicts.
Turning on the quotas on for one or more file systems.

For specific information about these procedures, see Setting Up Quotas (Task Map).

The following table describes the commands that you use to set up disk quotas.

Table 7–1 Commands for Setting Up Quotas


Command	Task	Man Page
`edquota`	Sets the hard limits and soft limits on the number of inodes and the amount of disk space for each user.	edquota(1M)
`quotacheck`	Examines each mounted UFS file system, comparing the file system's current disk usage against information stored in the file system's disk quota file. Then, resolves inconsistencies	quotacheck(1M)
`quotaon`	Activates the quotas for the specified file systems.	quotaon(1M)
`quota`	Displays users' disk quotas on mounted file systems to verify that the quotas have been correctly set up.	quota(1M)

Guidelines for Setting Up Quotas

Before you set up quotas, you need to determine how much disk space and how many inodes to allocate to each user. If you want to ensure that the total file system space is never exceeded, you can divide the total size of the file system between the number of users. For example, if three users share a 100-Mbyte slice and have equal disk space needs, you could allocate 33 Mbytes to each user.

In environments where not all users are likely to push their limits, you might want to set individual quotas so that they add up to more than the total size of the file system. For example, if three users share a 100-Mbyte slice, you could allocate 40 Mbytes to each user.

When you have established a quota for one user by using the edquota command, you can use this quota as a prototype to set the same quota for other users on the same file system.

Before you turn on the quotas, do the following:

First, configure the UFS file systems for the quotas.
Establish quotas for each user, and run the quotacheck command to check for consistency between current disk usage and quota files.
Run the quotacheck command periodically if systems are rebooted infrequently.

The quotas you set up with the edquota command are not enforced until you turn them on by using the quotaon command. If you have properly configured the quota files, the quotas are turned on automatically each time a system is rebooted and the file system is mounted.