Quota's Concept on RHEL/CentOS 6

  Quota allows Administrator to specify restriction in two ways :

  1) Restricting a user or a group by creating files in a specific location.

  2) Restricting a user or a group by the disk space in a specific location.

    

The idea behind quotas is that users are forced to stay under their disk consumption limit or with number of files in a particular location.

Quota is handled on a per user, per file system basis.

Quotas are of two types :

   User level quotas      - usrquota

   Group level quotas     - grpquota

To apply userquota

vi /etc/fstab

/dev/sda5     /home    ext4  defaults,usrquota 0 0

(add usrquota beside defaults)

#mount -o remount,rw /home

(to remount /home partition)

to check quotas

#quotacheck -cvug  /home

to on quota

# quotaon /home

to set quota for an user

# edquota -u  <username>

/dev/sda5      blocks    soft    hard inodes soft     hard

32          0          0         12        0         0

here blocks means the data already present in that users home directory

soft means at which space u want to send a warning to user 

hard means at which space u want to restrict user to write into his home directory

note: for both soft&hard we have to add block size

by defaults quotas will be in off mode we have to manually switchon quotas

#quotaon /home

to check:

1)login as user

type dd if=/dev/zero of=myfile bs=1024 count=10

dd =diskdrive

if = input file (/dev/zero means it's  a null file)

of = output file 

bs=blocksize(default in bytes)

count= howmany no.of blocks u want to create

to check quota as an admin

#repquota /home

to set users mahesh quota for user suresh

#edquota -p mahes suresh

To work with group quota

 to work with groupquota we have to create quota enabled partition

create a partition

format with ext4 file system

create a new mountpoint

#mount -o  usrquota,grpquota <mountpoint>

#quotacheck -cugv <qoutamountpoint>

edquota -g <groupname>