Difference between revisions of "Disk quota"

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[[Category: Security (English)]]
 
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From [[Wikipedia:Disk quota|Wikipedia]]:
 
From [[Wikipedia:Disk quota|Wikipedia]]:
 
:"''A '''disk quota''' is a limit set by a system administrator that restricts certain aspects of file system usage on modern operating systems. The function of setting quotas to disks is to allocate limited disk-space in a reasonable way.''"
 
:"''A '''disk quota''' is a limit set by a system administrator that restricts certain aspects of file system usage on modern operating systems. The function of setting quotas to disks is to allocate limited disk-space in a reasonable way.''"

Revision as of 17:22, 10 June 2011

From Wikipedia:

"A disk quota is a limit set by a system administrator that restricts certain aspects of file system usage on modern operating systems. The function of setting quotas to disks is to allocate limited disk-space in a reasonable way."

This article covers the installation and setup of disk quota.

Installing

Disk quota only requires one package:

# pacman -S quota-tools

Enabling

For journaled quota, see the notes in #Journaled quota.

1. First, edit Template:Filename to enable the quota mount option(s) on selected file systems:

 /dev/sda1 /home ext4 defaults 1 1
edit it as follows;
 /dev/sda1 /home ext4 defaults,usrquota 1 1
or aditionally enable the group quota mount option;
 /dev/sda1 /home ext4 defaults,usrquota,grpquota 1 1

2. Create the quota files in the file system:

 # touch /home/aquota.user
 # touch /home/aquota.group     # For group quota

2. The next step is to remount:

 # mount -vo remount /home

4. Create the quota index:

 # quotacheck -vgum /home
or for all partitions with the quota mount options in Template:Filename;
 # quotacheck -vguma

5. Finally, enable quotas:

 # quotaon -av
Tip: to automatically enable quota on boot, add Template:Codeline to Template:Filename.

Journaled quota

Enabling journaling for disk quota adds the same benefits journaled file systems do for forced shutdowns, meaning that data is less likely to become corrupt.

Setting up journaled quota is the same as above, except for the mount options:

/dev/sda1 /home ext4 defaults,usrjquota=aquota.user,jqfmt=vfsv0 1 1

or aditionally enable the group quota mount option;

/dev/sda1 /home ext4 defaults,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0 1 1

Configuring

Replace Template:Codeline as appropriate and edit the quota as root: Template:Command

Note: to edit group quotas, use Template:Codeline.
blocks
Number of 1k blocks currently used by Template:Codeline
inodes
Number of entries by Template:Codeline in directory file
soft
Max number of blocks/inodes Template:Codeline may have on partition before warning is issued and grace period countdown begins. If set to "0" (zero) then no limit is enforced.
hard
Max number of blocks/inodes Template:Codeline may have on partition. If set to "0" (zero) then no limit is enforced.


Example configuration:

Disk quotas for user testuser (uid 1000):
Filesystem      blocks       soft       hard     inodes     soft   hard       
/dev/sda1       695879       10000      15000     6741        0      0

The Template:Codeline limit means that once testuser uses over 10MB of space a warning email gets ensued, and after a period of time the soft limit gets enforced.

The Template:Codeline limit is stricter, so to speak; a user cannot go over this limit.


Next configure the Template:Codeline limit grace period:

# edquota -t

Managing

Checking for quota limits and advanced operations

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, Template:Codeline is used to give thorough information about the quota system: Template:Command

More resources