Controlling User Disk Space Usage

Quotas let system administrators control the size of UFS file systems by limiting the amount of disk space that individual users can acquire. Quotas are especially useful on file systems where user home directories reside.

After the quotas are in place, they can be changed to adjust the amount of disk space or number of inodes that users can consume. Additionally, quotas can be added or removed as system needs change. Also, 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.

After you have set up and turned on disk and inode quotas, you can check for users who exceed their quotas. You can also check quota information for entire file systems by using the following commands

quota Displays the quotas and disk usage within a file system for individual users on which quotas have been activated
repquota Displays the quotas and disk usage for all users on one or more file systems

Generally, you do not see quota in use these days due to the cost of disk space continues to fall and in most cases, the sysadmin simply watches disck space to identify users who might be using more than their fair share.

On a large system with many users, however, disk quotas can be an effective way to control disk space usage.

The quot command

Use the quot command to display how much disk space, in kilobytes, is being used by users. You do not need to implement disk quotas to use this command. The quot command can only be run by root. The syntax for the quot command is:

quot -options <file system>

The quot command has two options: -a Reports on all mounted file systems -f Includes the number of files

To display disk space being used by all users on all mounted file systems, type the following:

# quot -af
/dev/rdsk/c0t0d0s0 (/):
68743    4370   root
 162       18   lp
  31       14   uucp
   1        1   adm
/dev/rdsk/c0t0d0s6 (/usr):
1270388 50748   root
 1254      19   lp
 766       15   uucp
  10        3   bin
   1        1   adm
/dev/rdsk/c0t0d0s1 (/var):
63327    5232   root
  208       9   adm
   22      27   lp
   16      17   uucp
    4       4   daemon
    4       8   nobody
    2       2   smmsp
    1       3   dsmith
    1       1   bin
/dev/rdsk/c0t0d0s5 (/opt):
 2608     253   root
    2       2   lp
/dev/rdsk/c0t0d0s7 (/export/home):
  212     131   root
   68      56   mchurchi
   58      39   dsmith
    5       5   sharris
    4       4   jhaynes
    4       4   tpeters
    2       2   tfarar

The columns of information displayed represent kilobytes used, number of files, and owner, respectively.

To display a count of the number of files and space owned by each user for a specific file system, enter

# quot -f /dev/dsk/c0t0d0s7
 212     131   root
  68      56   mchurchi
  58      39   dsmith
   5       5   sharris
   4       4   jhaynes
   4       4   tpeters
   2       2   tfarar