First do:

yum install quota

Also you have to edit the edit the /etc/fstab and add:

usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0

If you do not need to set quotas for groups then omit the grpjquota=aquota.group, then in my fstab I have this:

UUID=b4a0be80-3a47-4609-af72-a30b7102593b /                       ext4    defaults        1 1
UUID=8f7f1ed5-4726-471f-a48e-76088180c099 /boot                   ext4    defaults        1 2
UUID=11315782-76c7-4380-b968-0bcef2f4b832 /home                   ext4    defaults,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0        1 2
UUID=4dcacd31-c789-4406-8a71-fe1579ac5f4f swap                    swap    defaults        0 0
tmpfs                   /dev/shm                tmpfs   defaults,nosuid,noexec,rw         0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/var/tempFS             /tmp                    ext4    loop,nosuid,noexec,rw   0 0

To create the quota files (aquota.user and aquota.group) on the file system, use the -c option of the quotacheck command. For example, if user and group quotas are enabled for the /home file system, create the files in the /home directory:

quotacheck -cug /home

The -c option specifies that the quota files should be created for each file system with quotas enabled, the -u option specifies to check for user quotas, and the -g option specifies to check for group quotas.

If neither the -u or -g options are specified, only the user quota file is created. If only -g is specified, only the group quota file is created.

 

After the files are created, run the following command to generate the table of current disk usage per file system with quotas enabled:

quotacheck -avugm

The options used are as follows:

  • a — Check all quota-enabled, locally-mounted file systems
  • v — Display verbose status information as the quota check proceeds
  • u — Check user disk quota information
  • g — Check group disk quota information

After quotacheck has finished running, the quota files corresponding to the enabled quotas (user and/or group) are populated with data for each quota-enabled locally-mounted file system such as /home

quotaon -avug

if you need to turn the quotas off then do:

quotaoff /home

or the equivalent

quotaon -f /home

The quota system is ready to go, now we have to set the quotas for every user:

edquota -u username

And we get:

Disk quotas for user username (uid 501):

  Filesystem                   blocks       soft       hard     inodes     soft     hard
  /dev/mapper/vg_aguila-lv_root         36        0          0         10        0        0

The system automatically uses the default editor.

If we want to set 5MB of quota for username then we edit the file to:

Disk quotas for user username (uid 501):

  Filesystem                   blocks       soft       hard     inodes     soft     hard
  /dev/mapper/vg_aguila-lv_root         36       5000          0         10        0        0

 

Gestão

Basics

Use this command to check for quotas on a specific partition:

# repquota /home

Use this command to check for all quotas that apply to a user:

# quota -u $USER

for groups;

# quota -g $GROUP

Copying quota settings

To copy quota from one user or group to the other, use this command:

# edquota -p user1 user2

User1 is the user you copy from, user2 is the user you copy quota to. Of course you can replace user with group, when necessary.

Multiple users

The idea is to make a temporary user acount, modify the quota settings for that user, and then copy the generated quota files for all users to use. After setting quota settings for quotauser, copy the settings:

# edquota -p quotauser `awk -F: '$3 > 999 {print $1}' /etc/passwd`

This applies the settings to users with a UID equal to or greater than 1000.

Other commands

There are several useful commands:

repquota -a      # Shows the status on disk usage
warnquota        # Can be used to warn the users about their quota
setquota         # Non-interactive quota setting--useful for scripting

Lasty, quotastats is used to give thorough information about the quota system:

$ quotastats
Number of dquot lookups: 101289
Number of dquot drops: 101271
Number of still active inodes with quota : 18
Number of dquot reads: 93
Number of dquot writes: 2077
Number of quotafile syncs: 134518740
Number of dquot cache hits: 7391
Number of allocated dquots: 90
Number of free dquots: 2036
Number of in use dquot entries (user/group): -1946

 

Fonte:

http://www.centos.org/docs/5/html/Deployment_Guide-en-US/ch-disk-quotas.html

http://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-disk-quotas-managing.html

https://wiki.archlinux.org/index.php/Disk_Quota#Journaled_quota